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Giant magnetocaloric effect in a Heusler Mn50Ni40In10 unidirectional crystal
Intermetallics 65 (2015) 10e14
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Intermetallics journal homepage: www.elsevier.com/locate/intermet
Giant magnetocaloric effect in a Heusler Mn50Ni40In10 unidirectional crystal Jian Ren a, b, Hongwei Li a, b, Shutong Feng a, b, Qijie Zhai a, Jianxun Fu a, Zhiping Luo c, Hongxing Zheng a, b, * a b c
State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China Laboratory for Microstructures, Shanghai University, Shanghai 200072, China Department of Chemistry and Physics, Fayetteville State University, Fayetteville, NC 28301, USA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 19 March 2015 Received in revised form 6 May 2015 Accepted 8 May 2015 Available online
A modified high-pressure optical zone-melting technique was used to grow a Mn-rich Heusler Mn50Ni40In10 unidirectional crystal. Experimental results showed that the produced unidirectional crystal underwent a magnetic transition in austenite, followed with a martensitic transformation from a ferromagnetic austenite to a ferromagnetic martensite upon cooling. Under a magnetic field change of 30 kOe, the total effective refrigeration capacities (RCtotal) reached as high as 231.58 J/kg when the magnetic field was applied along parallel to the crystal growth direction, or 246.79 J/kg when the magnetic field was applied along perpendicular to the crystal growth direction. It was suggested that this unidirectional crystal growing technique may provide an effective approach to enhance the magnetocaloric effect of Mn-rich Heusler materials. © 2015 Elsevier Ltd. All rights reserved.
Keywords: A. Shapeememory alloys B. Martensitic transformation B. Magnetic properties C. Crystal growth D. Microstructure
1. Introduction Although solid-state magnetocaloric effect (MCE) was firstly revealed in Fe by Warburg as early as in 1881 [1], there had been limited research activities on this old phenomenon until a practical magnetic heat pumping was made at room temperature using Gd by Brown in 1976 [2]. Afterwards, Pecharsky and Gschneidner observed giant magnetocaloric effect of Gd5(Si,Ge)4 in 1997 [3], with maximum magnetic entropy change DSM at least doubled that of Gd. This breakthrough rapidly facilitated the development of magnetic refrigeration technique. Up to date, several classes of magnetocaloric materials have been investigated, including Gd5(Si,Ge)4 [4e7], La(Fe,Si)13 [8,9], MnAs [10e13] and Heusler NieMn based materials [14e18]. Among them, Heusler NieMn based materials without rare-earth or toxic elements (such as As) were considered to be more suitable for practical applications. They have been investigated as intelligent actuators by taking their advantage of large magnetic-field-induced strain and shape memory effect (superelasticity) associated with the first-order * Corresponding author. State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China. Tel./fax: þ86 21 56334045. E-mail address: [email protected] (H. Zheng). http://dx.doi.org/10.1016/j.intermet.2015.05.004 0966-9795/© 2015 Elsevier Ltd. All rights reserved.
martensitic transformation [19,20]. Since Hu et al. reported a positive DSM of 4.1 J/kg$K in the vicinity of the first-order martensitic transition in polycrystalline NieMneGa under a low magnetic field change of 9 kOe in 2000 (inverse MCE) [21], plenty of investigations on MCE in Heusler NieMn based materials have been triggered. Krenke et al. reported DSM of 19 J/kg$K under 50 kOe in NieMneSn in 2005 [22], and Khan et al. reported enhanced DSM of 66.2 J/kg$K in Ni2þxMn1xGa (50 kOe) in 2005 [23], and 64 J/kg$K in Ni2Mn0.75Cu0.25Ga (50 kOe) in 2006 [24]. Mandal et al. obtained DSM as high as 86 J/kg$K in NieMneGa in 2009 (50 kOe) [25]. On the other hand, Zhang et al. proposed a magnetic refrigerator based on the characteristic of DSM, where both the first-order martensitic transformation (inverse MCE) and second-order magnetic transition in austenite (direct MCE) could be utilized in a refrigeration cycle [26]. In addition, it has been recognized that it was not fully reasonable to evaluate the magnetic refrigeration capacity of Heusler materials by only using DSM, since the magnetic hysteresis loss resulted from the first-order martensitic transformation cannot be ignored and thus it must be taken into account. An alternative physical parameter, total effective refrigeration capacity RCtotal from both transitions, was proposed to evaluate the MCE [27]. Recently, some researchers developed Mn-rich Mn2Ni(Ga,In,Sn) Heusler materials since higher Mn content was expected to
J. Ren et al. / Intermetallics 65 (2015) 10e14
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Fig. 1. Longitudinal optical images of the Mn50Ni40In10 unidirectional crystal at (a) initial stage and (b) stable zone. A small sample with size of 1 mm 1 mm 2 mm was taken from the stable zone after the crystal was annealed at 1073 K for 48 h.
enhance the MCE [28e31]. Hernando et al. reported the RCtotal reached ~148 J/kg in Mn50Ni40In10 melt-spun ribbons under a magnetic field change of 30 kOe [31], which was higher than most of reported values in Heusler NieMn based materials, for example, Ni50Mn37Sn13 (~82 J/kg, 30 kOe) [22] and Ni49Mn39Sn12 (~127 J/kg, 30 kOe) [32]. In the present work, a Mn-rich Heusler Mn50Ni40In10 unidirectional crystal was produced using a modified high-pressure optical zone-melting furnace to investigate its magnetocaloric effect. Using the unidirectional crystal, it is possible to apply the magnetic field along certain crystallographic directions to indentify the effect of crystallographic texture and tailor its MCE property.
2. Experimental The Mn50Ni40In10 (at.%) unidirectional crystal was grown using a modified high-pressure optical zone-melting furnace. Firstly, a button ingot was arc melted from pure Mn, Ni and In (purities higher than 99.99 wt.%) in argon gas atmosphere. The surface oxides of the ingot were mechanically removed, followed with a suction casting which yielded a rod with 8 mm in diameter and
Fig. 2. XRD patterns from (a) as-cast Mn50Ni40In10 master rod, and stable zone of the unidirectional crystal (b) unannealed and (c) annealed at 1073 K for 48 h.
~65 mm in length. Secondly, a master rod was placed into a transparent alumina tube and then fixed to a position above the center of a down puller. Two ellipsoidal mirrors with 650 W halogen lamps were used to heat the focused zone. After the quartz chamber was evacuated to 2 103 Pa, high-purity argon gas (99.999%) was backfilled to 0.8 MPa static pressure. Lastly, a piece of Ti bar hung on the upper puller was preheated for 40 min to consume residual oxygen in the quartz chamber prior to the crystal growth. The temperature of the molten zone was estimated to be ~1200 K. The pulling rate of 14 mm/h and rotation rate of 15 rpm were kept at constants during the growth process. More experimental details on the crystal growth have been described elsewhere [32,33]. Microstructural observations were performed using an optical microscope (Zeiss Axio Imager A2m). X-ray diffraction (XRD, DLMAX-2500) was employed to detect the crystal structure and growth orientation. After the crystal was annealed at 1073 K for 48 h, a small sample with size of 1 mm 1 mm 2 mm was cut from the stable zone for the magnetic measurements. Magnetic properties were carried out using physical property measurement systems (Quantum Design PPMS-9) under a magnetic field change up to 30 kOe. The magnetic field was applied along parallel (Hk) or perpendicular (H⊥) to the crystal growth directions, respectively (Fig. 1).
Fig. 3. Thermomagnetic curves measured under a magnetic field of 1 kOe for the Mn50Ni40In10 unidirectional crystal. The sample was taken from the stable zone after the crystal was annealed at 1073 K for 48 h. Insert: dM/dT vs T curves.
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J. Ren et al. / Intermetallics 65 (2015) 10e14
3. Results and discussion The longitudinal optical images of the Mn50Ni40In10 unidirectional crystal are shown in Fig. 1. One can roughly distinguish four different zones along the growth direction. The as-cast original alloy in Zone 1 shows randomly oriented equiaxed grains, with an average size of 80 mm. The high-temperature recrystallization resulted in a striking grain growth to 200 mm in Zone 2. Columnar grains grew parallel to the growth direction in Zone 3 and only several large columnar grains remained in Zone 4. Fig. 2a shows the XRD pattern from the Mn50Ni40In10 master rod, where random orientations exist in the L21 austenitic matrix. However, in the stable zone of the unidirectional crystal, the L21(420) diffraction peak intensifies obviously (Fig. 2b). After the sample was annealed at 1073 K for 48 h, no evident difference can be found (Fig. 2c). Some extra weak peaks, most likely from MnNi and Mn3Ni2In phases, are indicated by asterisks in Fig. 2a [34e36]. The magnetostructural transition behavior of the Heusler Mn50Ni40In10 unidirectional crystal was determined from the thermomagnetic (MeT) curves measured under a low magnetic field of 1 kOe within 100 K e 380 K (recorded at 2.5 K/min), as shown in Fig. 3. The insert is the dM/dT vs T curves. It is found that upon heating, the magnetization first rises dramatically associated with the martensitic transformation from ferromagnetic martensite to ferromagnetic austenite. The magnetization remains stable and then dropped sharply upon further heating owing to the ferromagnetic/paramagnetic transition in austenite [37]. The magnetostructural transition behavior is completely reversible upon cooling. The characteristic transition temperatures, including the austenite start and finish (As and Af) and martensite start and finish (Ms and Mf) temperatures, and the Curie point of austenite (TcA ), are determined to be 227 K, 258 K, 240.8 K, 208.4 K, and 362 K,
Fig. 5. Magnetic entropy change as a function of temperature under a magnetic field change of 30 kOe and the insert is the hysteresis loss.
respectively, as marked in Fig. 3. There exists a large thermal hysteresis of ~18.6 K (DT ¼ As Mf ) for the first-order martensitic transformation, which is much larger than that of the second-order magnetic transition in austenite (~4.5 K). Magnetization isotherms (M-H) were measured within 200 K e 380 K to evaluate the refrigeration capacity. In the present study, all magnetization isothermals were recorded in the following sequence: when the sample was initially cooled to 200 K under a zero-field (full martensitic state), the magnetic field was gradually increased from zero to a maximum strength of 30 kOe and then decreased to zero. After the MeH curve was measured, the temperature was raised to the next consecutive value at an interval
Fig. 4. Selected isothermal magnetization curves with magnetic field applied parallel to the growth direction (a,b) or perpendicular to the growth direction (c,d). The striped areas in Fig. 4a and c stand for the hysteresis losses.
J. Ren et al. / Intermetallics 65 (2015) 10e14
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Table 1 Physical parameters, including maximum magnetic entropy change DSM, working temperature range (DTFWHM ¼ Thot Tcold), refrigerant capacity RC, average hysteresis loss AHL and effective refrigeration capacity RCeff, and total effective refrigeration capacity RCtotal, values for the annealed Mn50Ni40In10 unidirectional crystal around the martensitic transformation (MT) and magnetic transition in austenite (TcA) under a magnetic field change of 30 kOe applied parallel (Hk) and (H⊥) perpendicular to the crystal growth direction, respectively. Field direction
Phase transition
DSM (J/kg$K)
Tcold (K)
Thot (K)
DTFWHM (K)
RC (J/kg)
AHL (J/kg)
RCeff (J/kg)
RCtotal (J/kg)
Hk
MT TA c MT TA c
10.73 1.91 10.28 1.89
235.64 269.43 235.81 269.71
251.62 372.70 253.19 370.66
15.98 103.27 17.38 100.95
129.78 154.86 144.41 151.06
53.06 0 48.68 0
76.72 154.86 95.73 151.06
231.58
H⊥
of 5 K. As presented in Fig. 4a for Hk, the maximum magnetization is about 7.5 emu/g for the sample in martensitic state at 200 K, which rises to 76 emu/g at 265 K in austenitic state. Typical metamagnetic transition behavior with magnetic hysteresis between field-up and field-down processes can be observed at 240 K, 245 K and 250 K [38]. A complete magnetic-field-induced transition can be achieved at a higher temperature of 250 K. At temperatures higher than 270 K, the isothermals turn to be more reversible, and metamagnetic behavior and hysteresis vanish (Fig. 4b). The MeH curves show similar features for H⊥ (Fig. 4c and d). As mentioned in the introduction, both martensitic transformation and magnetic transition in austenite can be utilized in a magnetic refrigeration cycle for Heusler materials, and the magnetic hysteresis loss from the first-order martensitic transformation must be taken into account. The hysteresis loss can be obtained by integrating the stripped areas, as marked in Fig. 4a and c. That is to say, the total effective refrigeration capacity RCtotal from both transitions should be considered to evaluate the magnetocaloric property. Refrigeration capacity (RC) is defined as R Thot RC ¼ Tcold jDSM ðTÞjdT [39], where Thot and Tcold are the corresponding temperatures at full width half the maximum peak value of DSM. DSM can be calculated using the Maxwell relation RH DSM ¼ 0 ðvM=vTÞdH [40] as a function of temperature, as shown in Fig. 5. Under a magnetic field change of 30 kOe for Hk, the RCmart across the martensitic transformation equals to 129.78 J/kg and the RCmeta values across the curie point of austenite equals to 154.86 J/kg; while for H⊥, RCmart ¼ 144.41 J/kg and RCmata ¼ 151.06 J/kg. Here, the superscript “mart” represents a martensitic transformation, and the “meta”, a magnetic transition in austenite. After subtracting average hysteresis losses (AHL), the
246.79
RCtotal (RCtotal ¼ RC mart þ RC meta AHL) reached 231.58 J/kg for Hk and 246.79 J/kg for H⊥, respectively. Table 1 lists all of the calculated results. The maximum DSM of Mn50Ni40In10 unidirectional crystal is significantly larger than melt-spun ribbons (~3.6 J/kg$K, 30 kOe) [31]. It can be attributed to the high magnetization discrepancy (DM ¼ 68.5 emu/g) between martensite and austenite across the martensitic transformation, which is typically ~45 emu/g for Mn50Ni40In10 melt-spun ribbons [28e31]. Large DM is beneficial to enhance the Zeeman energy EZeeman ¼ m0 DMH, where H is the strength of the applied magnetic field, and thus providing a stronger driving force for the metamagnetic transition. This is why we can observe a full magnetic-field-induced martensitic transformation in Mn50Ni40In10 unidirectional crystal under a field change of 30 kOe at the temperatures above 250 K (Fig. 4a and c). For the Mn50Ni40In10 unidirectional crystal, the characteristic transition temperatures shifted down 4 K with increasing the magnetic field of 10 kOe according to Fig. 6 (data in Fig. 6 are taken from Fig. 4a and b). Therefore, one can estimate the maximum absolute entropy change for the first-order magnetic-field-induced martensitic transformation near a value of ~17 J/kg$K via the ClausiuseClapeyron equation [41]. The maximum DSM values calculated based on the MeH curves in the vicinity of the first-order martensitic transformation at 30 kOe are 10.73 J/kg$K and 10.26 J/ kg$K for Hk and H⊥, respectively. Furthermore, it should be noted that Hk sample shows a higher initial magnetic susceptibility and quickly approaches to saturation as compared with H⊥ sample within the entire measured temperature range (Fig. 4). Thus, a smaller hysteresis loss is resulted for H⊥. For example, the hysteresis losses at 240 K are 51.6 J/kg for Hk and 40.7 J/kg for H⊥, respectively. Hernando et al. also observed similar hysteresis behavior in Mn50Ni40In10 ribbons, and similar phenomenon that both unidirectional crystal and ribbons demonstrated a higher initial magnetic susceptibility at lower magnetic fields for H⊥ [31]. As a result, the RCmart value increases from 76.72 J/kg (Hk) to 95.73 J/kg (H⊥). eff The RCmeta eff values are almost same. It is evident that whether under Hk or H⊥, the RCtotal values (231.58 J/kg for Hk and 246.79 J/kg for H⊥, 30 kOe) are much higher than the melt-spun Mn50Ni40In10 ribbons (~148 J/kg, 30 kOe) [31].
4. Conclusions
Fig. 6. Thermomagnetic curves measured under different magnetic fields for the Mn50Ni40In10 unidirectional crystal (data taken from Fig. 4a and b).
In summary, a Mn-rich Heusler Mn50Ni40In10 unidirectional crystal has been successfully prepared by using the modified highpressure optical zone-melting technique. The total effective refrigeration capacity reached 231.58 J/kg for Hk and 246.79 J/kg for H⊥ under a magnetic field change of 30 kOe, respectively. The enhancement of magnetic refrigeration capacity under H⊥ was mainly ascribed to the reduction of hysteresis loss in the vicinity of the first-order martensitic transformation. It indicated that highpressure optical zone-melting technique could effectively improve the magnetocaloric effect of Mn-rich Heusler materials.
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Author agreement We claim that all authors have participated sufficiently in this work to take public responsibility for it; all authors have reviewed the final version of the manuscript and approve it for publication; and neither this manuscript nor one with substantially similar content under our authorship has been published or is being considered for publication elsewhere. Acknowledgments The authors gratefully acknowledge the support from the National Natural Science Foundation of China (51474144, 51201096) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (20123108120019). References [1] Warburg E. Magnetische untersuchungen über einige wirkungen der coerzitivkraft. Ann Phys 1881;13:141e64. [2] Brown GV. Magnetic heat pumping near room temperature. J Appl Phys 1976;47(8):3673e80. [3] Pecharsky VK, Gschneidner Jr KA. Tunable magnetic regenerator alloys with a giant magnetocaloric effect for magnetic refrigeration from ~20 to ~290 K. Appl Phys Lett 1997;70:3299. [4] Haskel D, Lee YB, Harmon BN, Islam Z, Lang JC, Srajer G, et al. Role of Ge in bridging ferromagnetism in the giant magnetocaloric Gd5(Ge1xSix)4 alloys. Phys Rev Lett 2007;98:247205. [5] Misra S, Miller GJ. Gd5-xYxTt4 (Tt ¼ Si or Ge): effect of metal substitution on structure, bonding, and magnetism. J Am Chem Soc 2008;130(42):13900e11. [6] Tseng YC, Paudyal D, Mudryk Ya, Pecharsky VK, Gschneidner Jr KA, Haskel D. Electronic contribution to the enhancement of the ferromagnetic ordering temperature by Si substitution in Gd5(SixGe1x)4. Phys Rev B 2013;88(5): 054428. [7] Min JX, Zhong XC, Franco V, Tian HC, Liu ZW, Zheng ZG, et al. Structure, magnetic properties and giant magnetocaloric effect of Tb4Gd1Si2.035Ge1.935Mn0.03 alloy. Intermetallics 2015;57:68e72. [8] Hu FX, Shen BG, Sun JR, Cheng ZH, Rao GH, Zhang XX. Influence of negative lattice expansion and metamagnetic transition on magnetic entropy change in the compound LaFe11.4Si1.6. Appl Phys Lett 2001;78:3675. [9] Balli M, Fruchart D, Gignoux D. Optimization of La(Fe,Co)13xSix based compounds for magnetic refrigeration. J Phys Condens Matter 2007;19(23): 236230. [10] de Medeiros Jr LG, de Oliveira NA, Troper A. Giant magnetocaloric and barocaloric effects in Mn(As1xSbx). J Alloy Compd 2010;501(2):177e82. [11] Tegus O, Bruck E, Buschow KHJ, de Boer FR. Transition-metal-based magnetic refrigerants for room-temperature applications. Nature 2002;415:150e2. ska S, Zubov E, Sivachenko A, Gribanov I, et al. [12] Szymczak R, Nedelko N, Lewin Comparison of magnetocaloric properties of the Mn2xFexP0.5As0.5 (x ¼ 1.0 and 0.7) compounds. Solid State Sci 2014;36:29e34. [13] de Campos A, da Luz MS, de Campos A, Coelho AA, Cardoso LP, dos Santos AO, et al. Investigations in MnAs1xSbx: experimental validation of a new magnetocaloric composite. J Magn Magn Mater 2015;374:342e4. [14] Zheng HX, Wang W, Xue SC, Zhai QJ, Frenzel J, Luo ZP. Composition-dependent crystal structure and martensitic transformation in Heusler NieMneSn alloys. Acta Mater 2013;61(12):4648e56. [15] Liu J, Gottschall T, Skokov KP, Moore JD, Gutfleisch O. Giant magnetocaloric effect driven by structural transitions. Nat Mater 2012;11(7):620e6. [16] Zheng HX, Wu DZ, Xue SC, Frenzel J, Eggeler G, Zhai QJ. Martensitic transformation in rapidly solidified Heusler Ni49Mn39Sn12 ribbons. Acta Mater 2011;59(14):5692e9. [17] Huang YJ, Hua QD, Liu J, Zeng L, Zhang DF, Li JG. Banded-like morphology and martensitic transformation of dual-phase NieMneIn magnetic shape memory alloy with enhanced ductility. Acta Mater 2013;61:5702e12.
rez-Landaza bal I, Recarte V, Torrens-Serra J, Cesari E. Relaxation effects in [18] Pe magnetic-field-induced martensitic transformation of an NieMneIneCo alloy. Acta Mater 2014;71:117e25. [19] Qian MF, Zhang XX, Witherspoon C, Sun JF, Müllner P. Superelasticity and shape memory effects in polycrystalline NieMneGa microwires. J Alloy Compd 2013;577:S296e9. [20] Chernenko VA, Villa E, Besseghini S, Barandiaran JM. Giant two-way shape memory effect in high-temperature NieMneGa single crystal. Phys Procedia 2010;10:94e8. [21] Hu FX, Shen BG, Sun JR. Magnetic entropy change in Ni51.5Mn22.7Ga25.8 alloy. Appl Phys Lett 2000;73(23):3460e2. ~ osa LI, et al. Inverse [22] Krenke T, Duman E, Acet M, Wassermann EF, Moya X, Man magnetocaloric effect in ferromagnetic NieMneSn alloys. Nat Mater 2005;4: 450e4. [23] Khan M, Stadler S, Craig J, Mitchell J, Ali N. The overlap of first- and secondorder phase transitions and related magnetic entropy changes in Ni2þxMn1xGa Heusler alloys. IEEE Trans Magn 2006;42:3108e10. [24] Stadler S, Khan M, Mitchell J, Ali N, Gomes AM, Dubenko I, et al. Magnetocaloric properties of Ni2Mn1xCuxGa. Appl Phys Lett 2006;88:192511. [25] Mandal K, Pal D, Scheerbaum N, Lyubina J, Gutfleisch O. Effect of pressure on the magnetocaloric properties of nickel-rich NieMneGa Heusler alloys. J Appl Phys 2009;105:73509. [26] Zhang XX, Zhang B, Yu SY, Liu ZH, Xu WJ, Liu GD, et al. Combined giant inverse and normal magnetocaloric effect for room temperature magnetic cooling. Phys Rev B 2007;76:132403. [27] Wu DZ, Xue SC, Frenzel J, Eggeler G, Zhai QJ, Zheng HX. Atomic ordering effect in Ni50Mn37Sn13 magnetocaloric ribbons. Mater Sci Eng A 2012;534:568e72. nchez Llamazares JL, Sanchez T, Santos JD, Pe rez MJ, Sanchez ML, [28] Sa Hernando B, et al. Martensitic phase transformation in rapidly solidified Mn50Ni40In10 alloy ribbons. Appl Phys Lett 2008;92:012513. nchez Llamazares JL, Hernando B, Prida VM, García C, Gonza lez J, Varga R, [29] Sa et al. Magnetic field influence on the structural transformation in ferromagnetic shape memory alloy Mn50Ni40In10 melt spun ribbons. J Appl Phys 2009;105:07A945.. nchez Llamazares JL, Santos JD, Sa nchez ML, Escoda LI, Suno ~ l JJ, [30] Hernando B, Sa et al. Grain oriented NiMnSn and NiMnIn Heusler alloys ribbons produced by melt spinning: martensitic transformation and magnetic properties. J Magn Magn Mater 2009;321:763e8. nchez LIamazares JL, Prida VM, Baldomir D, Serantes D, IIyn M, [31] Hernando B, Sa et al. Magnetocaloric effect in preferentially textured Mn50Ni40In10 melt spun ribbons. Appl Phys Lett 2009;94:222502. [32] Ren J, Li HW, Yu JK, Feng ST, Zhai QJ, Fu JX, et al. Enhanced magnetocaloric effect in Heusler NieMneSn unidirectional crystal. J Alloy Compd 2015;634: 65e9. [33] Yu JK, Ren J, Li HX, Fu JX, Zhai QJ, Luo ZP, et al. A new approach to grow Heusler NieMneSn unidirectional crystal. J Cryst Growth 2014;402:147e50. [34] Miyamoto T, Nagasako M, Kainuma R. Phase equilibria in the NieMneIn alloy system. J Alloy Compd 2013;549:57e63. [35] Pathak AK, Dubenko I, Stadler S, Ali N. The effect of partial substitution of In by Si on the phase transitions and respective magnetic entropy changes of Ni50Mn35In15 Heusler alloy. J Phys D Appl Phys 2008;41:202004. [36] Ao WQ, Liu FS, Li JQ, Du Y, Liu FL. Isothermal section of the NieMneIn ternary system at 773 K. J Alloy Compd 2015;622:149e54. nchez-Alarcos V, Pe rez-Landaz lez J, Rodríguez[37] Sa abal JI, Recarte V, Lucia I, Ve n JA. Effect of high-temperature quenching on the magnetostructural Velaza transformations and the long-range atomic order of NieMneSn and NieMneSb metamagnetic shape memory alloys. Acta Mater 2013;61(12): 4676e82. [38] Pathak AK, Khan M, Dubenko I, Stadler S, Ali N. Large magnetic entropy change in Ni50Mn50xInx Heusler alloys. Appl Phys Lett 2007;90:262504. [39] Umetsu RY, Kainuma R, Amako Y, Taniguchi Y, Kanomata T, Fukushima K, €ssbauer study on martensite phase in Ni50Mn36.557Fe0.5Sn13 metaet al. Mo magnetic shape memory alloy. Appl Phys Lett 2008;93:042509. [40] Franco V, Bl azquez JS, Ingale B, Conde A. The magnetocaloric effect and magnetic refrigeration near room temperature: materials and models. Annu Rev Mater Res 2012;42:305e42. ~ osa LI, Planes A, Casanova F, Batlle X, Labarta A. Multiscale origin [41] Marcos J, Man of the magnetocaloric effect in NieMneGa shape-memory alloys. Phys Rev B 2003;68:094401.
Contents lists available at ScienceDirect
Intermetallics journal homepage: www.elsevier.com/locate/intermet
Giant magnetocaloric effect in a Heusler Mn50Ni40In10 unidirectional crystal Jian Ren a, b, Hongwei Li a, b, Shutong Feng a, b, Qijie Zhai a, Jianxun Fu a, Zhiping Luo c, Hongxing Zheng a, b, * a b c
State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China Laboratory for Microstructures, Shanghai University, Shanghai 200072, China Department of Chemistry and Physics, Fayetteville State University, Fayetteville, NC 28301, USA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 19 March 2015 Received in revised form 6 May 2015 Accepted 8 May 2015 Available online
A modified high-pressure optical zone-melting technique was used to grow a Mn-rich Heusler Mn50Ni40In10 unidirectional crystal. Experimental results showed that the produced unidirectional crystal underwent a magnetic transition in austenite, followed with a martensitic transformation from a ferromagnetic austenite to a ferromagnetic martensite upon cooling. Under a magnetic field change of 30 kOe, the total effective refrigeration capacities (RCtotal) reached as high as 231.58 J/kg when the magnetic field was applied along parallel to the crystal growth direction, or 246.79 J/kg when the magnetic field was applied along perpendicular to the crystal growth direction. It was suggested that this unidirectional crystal growing technique may provide an effective approach to enhance the magnetocaloric effect of Mn-rich Heusler materials. © 2015 Elsevier Ltd. All rights reserved.
Keywords: A. Shapeememory alloys B. Martensitic transformation B. Magnetic properties C. Crystal growth D. Microstructure
1. Introduction Although solid-state magnetocaloric effect (MCE) was firstly revealed in Fe by Warburg as early as in 1881 [1], there had been limited research activities on this old phenomenon until a practical magnetic heat pumping was made at room temperature using Gd by Brown in 1976 [2]. Afterwards, Pecharsky and Gschneidner observed giant magnetocaloric effect of Gd5(Si,Ge)4 in 1997 [3], with maximum magnetic entropy change DSM at least doubled that of Gd. This breakthrough rapidly facilitated the development of magnetic refrigeration technique. Up to date, several classes of magnetocaloric materials have been investigated, including Gd5(Si,Ge)4 [4e7], La(Fe,Si)13 [8,9], MnAs [10e13] and Heusler NieMn based materials [14e18]. Among them, Heusler NieMn based materials without rare-earth or toxic elements (such as As) were considered to be more suitable for practical applications. They have been investigated as intelligent actuators by taking their advantage of large magnetic-field-induced strain and shape memory effect (superelasticity) associated with the first-order * Corresponding author. State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072, China. Tel./fax: þ86 21 56334045. E-mail address: [email protected] (H. Zheng). http://dx.doi.org/10.1016/j.intermet.2015.05.004 0966-9795/© 2015 Elsevier Ltd. All rights reserved.
martensitic transformation [19,20]. Since Hu et al. reported a positive DSM of 4.1 J/kg$K in the vicinity of the first-order martensitic transition in polycrystalline NieMneGa under a low magnetic field change of 9 kOe in 2000 (inverse MCE) [21], plenty of investigations on MCE in Heusler NieMn based materials have been triggered. Krenke et al. reported DSM of 19 J/kg$K under 50 kOe in NieMneSn in 2005 [22], and Khan et al. reported enhanced DSM of 66.2 J/kg$K in Ni2þxMn1xGa (50 kOe) in 2005 [23], and 64 J/kg$K in Ni2Mn0.75Cu0.25Ga (50 kOe) in 2006 [24]. Mandal et al. obtained DSM as high as 86 J/kg$K in NieMneGa in 2009 (50 kOe) [25]. On the other hand, Zhang et al. proposed a magnetic refrigerator based on the characteristic of DSM, where both the first-order martensitic transformation (inverse MCE) and second-order magnetic transition in austenite (direct MCE) could be utilized in a refrigeration cycle [26]. In addition, it has been recognized that it was not fully reasonable to evaluate the magnetic refrigeration capacity of Heusler materials by only using DSM, since the magnetic hysteresis loss resulted from the first-order martensitic transformation cannot be ignored and thus it must be taken into account. An alternative physical parameter, total effective refrigeration capacity RCtotal from both transitions, was proposed to evaluate the MCE [27]. Recently, some researchers developed Mn-rich Mn2Ni(Ga,In,Sn) Heusler materials since higher Mn content was expected to
J. Ren et al. / Intermetallics 65 (2015) 10e14
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Fig. 1. Longitudinal optical images of the Mn50Ni40In10 unidirectional crystal at (a) initial stage and (b) stable zone. A small sample with size of 1 mm 1 mm 2 mm was taken from the stable zone after the crystal was annealed at 1073 K for 48 h.
enhance the MCE [28e31]. Hernando et al. reported the RCtotal reached ~148 J/kg in Mn50Ni40In10 melt-spun ribbons under a magnetic field change of 30 kOe [31], which was higher than most of reported values in Heusler NieMn based materials, for example, Ni50Mn37Sn13 (~82 J/kg, 30 kOe) [22] and Ni49Mn39Sn12 (~127 J/kg, 30 kOe) [32]. In the present work, a Mn-rich Heusler Mn50Ni40In10 unidirectional crystal was produced using a modified high-pressure optical zone-melting furnace to investigate its magnetocaloric effect. Using the unidirectional crystal, it is possible to apply the magnetic field along certain crystallographic directions to indentify the effect of crystallographic texture and tailor its MCE property.
2. Experimental The Mn50Ni40In10 (at.%) unidirectional crystal was grown using a modified high-pressure optical zone-melting furnace. Firstly, a button ingot was arc melted from pure Mn, Ni and In (purities higher than 99.99 wt.%) in argon gas atmosphere. The surface oxides of the ingot were mechanically removed, followed with a suction casting which yielded a rod with 8 mm in diameter and
Fig. 2. XRD patterns from (a) as-cast Mn50Ni40In10 master rod, and stable zone of the unidirectional crystal (b) unannealed and (c) annealed at 1073 K for 48 h.
~65 mm in length. Secondly, a master rod was placed into a transparent alumina tube and then fixed to a position above the center of a down puller. Two ellipsoidal mirrors with 650 W halogen lamps were used to heat the focused zone. After the quartz chamber was evacuated to 2 103 Pa, high-purity argon gas (99.999%) was backfilled to 0.8 MPa static pressure. Lastly, a piece of Ti bar hung on the upper puller was preheated for 40 min to consume residual oxygen in the quartz chamber prior to the crystal growth. The temperature of the molten zone was estimated to be ~1200 K. The pulling rate of 14 mm/h and rotation rate of 15 rpm were kept at constants during the growth process. More experimental details on the crystal growth have been described elsewhere [32,33]. Microstructural observations were performed using an optical microscope (Zeiss Axio Imager A2m). X-ray diffraction (XRD, DLMAX-2500) was employed to detect the crystal structure and growth orientation. After the crystal was annealed at 1073 K for 48 h, a small sample with size of 1 mm 1 mm 2 mm was cut from the stable zone for the magnetic measurements. Magnetic properties were carried out using physical property measurement systems (Quantum Design PPMS-9) under a magnetic field change up to 30 kOe. The magnetic field was applied along parallel (Hk) or perpendicular (H⊥) to the crystal growth directions, respectively (Fig. 1).
Fig. 3. Thermomagnetic curves measured under a magnetic field of 1 kOe for the Mn50Ni40In10 unidirectional crystal. The sample was taken from the stable zone after the crystal was annealed at 1073 K for 48 h. Insert: dM/dT vs T curves.
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3. Results and discussion The longitudinal optical images of the Mn50Ni40In10 unidirectional crystal are shown in Fig. 1. One can roughly distinguish four different zones along the growth direction. The as-cast original alloy in Zone 1 shows randomly oriented equiaxed grains, with an average size of 80 mm. The high-temperature recrystallization resulted in a striking grain growth to 200 mm in Zone 2. Columnar grains grew parallel to the growth direction in Zone 3 and only several large columnar grains remained in Zone 4. Fig. 2a shows the XRD pattern from the Mn50Ni40In10 master rod, where random orientations exist in the L21 austenitic matrix. However, in the stable zone of the unidirectional crystal, the L21(420) diffraction peak intensifies obviously (Fig. 2b). After the sample was annealed at 1073 K for 48 h, no evident difference can be found (Fig. 2c). Some extra weak peaks, most likely from MnNi and Mn3Ni2In phases, are indicated by asterisks in Fig. 2a [34e36]. The magnetostructural transition behavior of the Heusler Mn50Ni40In10 unidirectional crystal was determined from the thermomagnetic (MeT) curves measured under a low magnetic field of 1 kOe within 100 K e 380 K (recorded at 2.5 K/min), as shown in Fig. 3. The insert is the dM/dT vs T curves. It is found that upon heating, the magnetization first rises dramatically associated with the martensitic transformation from ferromagnetic martensite to ferromagnetic austenite. The magnetization remains stable and then dropped sharply upon further heating owing to the ferromagnetic/paramagnetic transition in austenite [37]. The magnetostructural transition behavior is completely reversible upon cooling. The characteristic transition temperatures, including the austenite start and finish (As and Af) and martensite start and finish (Ms and Mf) temperatures, and the Curie point of austenite (TcA ), are determined to be 227 K, 258 K, 240.8 K, 208.4 K, and 362 K,
Fig. 5. Magnetic entropy change as a function of temperature under a magnetic field change of 30 kOe and the insert is the hysteresis loss.
respectively, as marked in Fig. 3. There exists a large thermal hysteresis of ~18.6 K (DT ¼ As Mf ) for the first-order martensitic transformation, which is much larger than that of the second-order magnetic transition in austenite (~4.5 K). Magnetization isotherms (M-H) were measured within 200 K e 380 K to evaluate the refrigeration capacity. In the present study, all magnetization isothermals were recorded in the following sequence: when the sample was initially cooled to 200 K under a zero-field (full martensitic state), the magnetic field was gradually increased from zero to a maximum strength of 30 kOe and then decreased to zero. After the MeH curve was measured, the temperature was raised to the next consecutive value at an interval
Fig. 4. Selected isothermal magnetization curves with magnetic field applied parallel to the growth direction (a,b) or perpendicular to the growth direction (c,d). The striped areas in Fig. 4a and c stand for the hysteresis losses.
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Table 1 Physical parameters, including maximum magnetic entropy change DSM, working temperature range (DTFWHM ¼ Thot Tcold), refrigerant capacity RC, average hysteresis loss AHL and effective refrigeration capacity RCeff, and total effective refrigeration capacity RCtotal, values for the annealed Mn50Ni40In10 unidirectional crystal around the martensitic transformation (MT) and magnetic transition in austenite (TcA) under a magnetic field change of 30 kOe applied parallel (Hk) and (H⊥) perpendicular to the crystal growth direction, respectively. Field direction
Phase transition
DSM (J/kg$K)
Tcold (K)
Thot (K)
DTFWHM (K)
RC (J/kg)
AHL (J/kg)
RCeff (J/kg)
RCtotal (J/kg)
Hk
MT TA c MT TA c
10.73 1.91 10.28 1.89
235.64 269.43 235.81 269.71
251.62 372.70 253.19 370.66
15.98 103.27 17.38 100.95
129.78 154.86 144.41 151.06
53.06 0 48.68 0
76.72 154.86 95.73 151.06
231.58
H⊥
of 5 K. As presented in Fig. 4a for Hk, the maximum magnetization is about 7.5 emu/g for the sample in martensitic state at 200 K, which rises to 76 emu/g at 265 K in austenitic state. Typical metamagnetic transition behavior with magnetic hysteresis between field-up and field-down processes can be observed at 240 K, 245 K and 250 K [38]. A complete magnetic-field-induced transition can be achieved at a higher temperature of 250 K. At temperatures higher than 270 K, the isothermals turn to be more reversible, and metamagnetic behavior and hysteresis vanish (Fig. 4b). The MeH curves show similar features for H⊥ (Fig. 4c and d). As mentioned in the introduction, both martensitic transformation and magnetic transition in austenite can be utilized in a magnetic refrigeration cycle for Heusler materials, and the magnetic hysteresis loss from the first-order martensitic transformation must be taken into account. The hysteresis loss can be obtained by integrating the stripped areas, as marked in Fig. 4a and c. That is to say, the total effective refrigeration capacity RCtotal from both transitions should be considered to evaluate the magnetocaloric property. Refrigeration capacity (RC) is defined as R Thot RC ¼ Tcold jDSM ðTÞjdT [39], where Thot and Tcold are the corresponding temperatures at full width half the maximum peak value of DSM. DSM can be calculated using the Maxwell relation RH DSM ¼ 0 ðvM=vTÞdH [40] as a function of temperature, as shown in Fig. 5. Under a magnetic field change of 30 kOe for Hk, the RCmart across the martensitic transformation equals to 129.78 J/kg and the RCmeta values across the curie point of austenite equals to 154.86 J/kg; while for H⊥, RCmart ¼ 144.41 J/kg and RCmata ¼ 151.06 J/kg. Here, the superscript “mart” represents a martensitic transformation, and the “meta”, a magnetic transition in austenite. After subtracting average hysteresis losses (AHL), the
246.79
RCtotal (RCtotal ¼ RC mart þ RC meta AHL) reached 231.58 J/kg for Hk and 246.79 J/kg for H⊥, respectively. Table 1 lists all of the calculated results. The maximum DSM of Mn50Ni40In10 unidirectional crystal is significantly larger than melt-spun ribbons (~3.6 J/kg$K, 30 kOe) [31]. It can be attributed to the high magnetization discrepancy (DM ¼ 68.5 emu/g) between martensite and austenite across the martensitic transformation, which is typically ~45 emu/g for Mn50Ni40In10 melt-spun ribbons [28e31]. Large DM is beneficial to enhance the Zeeman energy EZeeman ¼ m0 DMH, where H is the strength of the applied magnetic field, and thus providing a stronger driving force for the metamagnetic transition. This is why we can observe a full magnetic-field-induced martensitic transformation in Mn50Ni40In10 unidirectional crystal under a field change of 30 kOe at the temperatures above 250 K (Fig. 4a and c). For the Mn50Ni40In10 unidirectional crystal, the characteristic transition temperatures shifted down 4 K with increasing the magnetic field of 10 kOe according to Fig. 6 (data in Fig. 6 are taken from Fig. 4a and b). Therefore, one can estimate the maximum absolute entropy change for the first-order magnetic-field-induced martensitic transformation near a value of ~17 J/kg$K via the ClausiuseClapeyron equation [41]. The maximum DSM values calculated based on the MeH curves in the vicinity of the first-order martensitic transformation at 30 kOe are 10.73 J/kg$K and 10.26 J/ kg$K for Hk and H⊥, respectively. Furthermore, it should be noted that Hk sample shows a higher initial magnetic susceptibility and quickly approaches to saturation as compared with H⊥ sample within the entire measured temperature range (Fig. 4). Thus, a smaller hysteresis loss is resulted for H⊥. For example, the hysteresis losses at 240 K are 51.6 J/kg for Hk and 40.7 J/kg for H⊥, respectively. Hernando et al. also observed similar hysteresis behavior in Mn50Ni40In10 ribbons, and similar phenomenon that both unidirectional crystal and ribbons demonstrated a higher initial magnetic susceptibility at lower magnetic fields for H⊥ [31]. As a result, the RCmart value increases from 76.72 J/kg (Hk) to 95.73 J/kg (H⊥). eff The RCmeta eff values are almost same. It is evident that whether under Hk or H⊥, the RCtotal values (231.58 J/kg for Hk and 246.79 J/kg for H⊥, 30 kOe) are much higher than the melt-spun Mn50Ni40In10 ribbons (~148 J/kg, 30 kOe) [31].
4. Conclusions
Fig. 6. Thermomagnetic curves measured under different magnetic fields for the Mn50Ni40In10 unidirectional crystal (data taken from Fig. 4a and b).
In summary, a Mn-rich Heusler Mn50Ni40In10 unidirectional crystal has been successfully prepared by using the modified highpressure optical zone-melting technique. The total effective refrigeration capacity reached 231.58 J/kg for Hk and 246.79 J/kg for H⊥ under a magnetic field change of 30 kOe, respectively. The enhancement of magnetic refrigeration capacity under H⊥ was mainly ascribed to the reduction of hysteresis loss in the vicinity of the first-order martensitic transformation. It indicated that highpressure optical zone-melting technique could effectively improve the magnetocaloric effect of Mn-rich Heusler materials.
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Author agreement We claim that all authors have participated sufficiently in this work to take public responsibility for it; all authors have reviewed the final version of the manuscript and approve it for publication; and neither this manuscript nor one with substantially similar content under our authorship has been published or is being considered for publication elsewhere. Acknowledgments The authors gratefully acknowledge the support from the National Natural Science Foundation of China (51474144, 51201096) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (20123108120019). References [1] Warburg E. Magnetische untersuchungen über einige wirkungen der coerzitivkraft. Ann Phys 1881;13:141e64. [2] Brown GV. Magnetic heat pumping near room temperature. J Appl Phys 1976;47(8):3673e80. [3] Pecharsky VK, Gschneidner Jr KA. Tunable magnetic regenerator alloys with a giant magnetocaloric effect for magnetic refrigeration from ~20 to ~290 K. Appl Phys Lett 1997;70:3299. [4] Haskel D, Lee YB, Harmon BN, Islam Z, Lang JC, Srajer G, et al. Role of Ge in bridging ferromagnetism in the giant magnetocaloric Gd5(Ge1xSix)4 alloys. Phys Rev Lett 2007;98:247205. [5] Misra S, Miller GJ. Gd5-xYxTt4 (Tt ¼ Si or Ge): effect of metal substitution on structure, bonding, and magnetism. J Am Chem Soc 2008;130(42):13900e11. [6] Tseng YC, Paudyal D, Mudryk Ya, Pecharsky VK, Gschneidner Jr KA, Haskel D. Electronic contribution to the enhancement of the ferromagnetic ordering temperature by Si substitution in Gd5(SixGe1x)4. Phys Rev B 2013;88(5): 054428. [7] Min JX, Zhong XC, Franco V, Tian HC, Liu ZW, Zheng ZG, et al. Structure, magnetic properties and giant magnetocaloric effect of Tb4Gd1Si2.035Ge1.935Mn0.03 alloy. Intermetallics 2015;57:68e72. [8] Hu FX, Shen BG, Sun JR, Cheng ZH, Rao GH, Zhang XX. Influence of negative lattice expansion and metamagnetic transition on magnetic entropy change in the compound LaFe11.4Si1.6. Appl Phys Lett 2001;78:3675. [9] Balli M, Fruchart D, Gignoux D. Optimization of La(Fe,Co)13xSix based compounds for magnetic refrigeration. J Phys Condens Matter 2007;19(23): 236230. [10] de Medeiros Jr LG, de Oliveira NA, Troper A. Giant magnetocaloric and barocaloric effects in Mn(As1xSbx). J Alloy Compd 2010;501(2):177e82. [11] Tegus O, Bruck E, Buschow KHJ, de Boer FR. Transition-metal-based magnetic refrigerants for room-temperature applications. Nature 2002;415:150e2. ska S, Zubov E, Sivachenko A, Gribanov I, et al. [12] Szymczak R, Nedelko N, Lewin Comparison of magnetocaloric properties of the Mn2xFexP0.5As0.5 (x ¼ 1.0 and 0.7) compounds. Solid State Sci 2014;36:29e34. [13] de Campos A, da Luz MS, de Campos A, Coelho AA, Cardoso LP, dos Santos AO, et al. Investigations in MnAs1xSbx: experimental validation of a new magnetocaloric composite. J Magn Magn Mater 2015;374:342e4. [14] Zheng HX, Wang W, Xue SC, Zhai QJ, Frenzel J, Luo ZP. Composition-dependent crystal structure and martensitic transformation in Heusler NieMneSn alloys. Acta Mater 2013;61(12):4648e56. [15] Liu J, Gottschall T, Skokov KP, Moore JD, Gutfleisch O. Giant magnetocaloric effect driven by structural transitions. Nat Mater 2012;11(7):620e6. [16] Zheng HX, Wu DZ, Xue SC, Frenzel J, Eggeler G, Zhai QJ. Martensitic transformation in rapidly solidified Heusler Ni49Mn39Sn12 ribbons. Acta Mater 2011;59(14):5692e9. [17] Huang YJ, Hua QD, Liu J, Zeng L, Zhang DF, Li JG. Banded-like morphology and martensitic transformation of dual-phase NieMneIn magnetic shape memory alloy with enhanced ductility. Acta Mater 2013;61:5702e12.
rez-Landaza bal I, Recarte V, Torrens-Serra J, Cesari E. Relaxation effects in [18] Pe magnetic-field-induced martensitic transformation of an NieMneIneCo alloy. Acta Mater 2014;71:117e25. [19] Qian MF, Zhang XX, Witherspoon C, Sun JF, Müllner P. Superelasticity and shape memory effects in polycrystalline NieMneGa microwires. J Alloy Compd 2013;577:S296e9. [20] Chernenko VA, Villa E, Besseghini S, Barandiaran JM. Giant two-way shape memory effect in high-temperature NieMneGa single crystal. Phys Procedia 2010;10:94e8. [21] Hu FX, Shen BG, Sun JR. Magnetic entropy change in Ni51.5Mn22.7Ga25.8 alloy. Appl Phys Lett 2000;73(23):3460e2. ~ osa LI, et al. Inverse [22] Krenke T, Duman E, Acet M, Wassermann EF, Moya X, Man magnetocaloric effect in ferromagnetic NieMneSn alloys. Nat Mater 2005;4: 450e4. [23] Khan M, Stadler S, Craig J, Mitchell J, Ali N. The overlap of first- and secondorder phase transitions and related magnetic entropy changes in Ni2þxMn1xGa Heusler alloys. IEEE Trans Magn 2006;42:3108e10. [24] Stadler S, Khan M, Mitchell J, Ali N, Gomes AM, Dubenko I, et al. Magnetocaloric properties of Ni2Mn1xCuxGa. Appl Phys Lett 2006;88:192511. [25] Mandal K, Pal D, Scheerbaum N, Lyubina J, Gutfleisch O. Effect of pressure on the magnetocaloric properties of nickel-rich NieMneGa Heusler alloys. J Appl Phys 2009;105:73509. [26] Zhang XX, Zhang B, Yu SY, Liu ZH, Xu WJ, Liu GD, et al. Combined giant inverse and normal magnetocaloric effect for room temperature magnetic cooling. Phys Rev B 2007;76:132403. [27] Wu DZ, Xue SC, Frenzel J, Eggeler G, Zhai QJ, Zheng HX. Atomic ordering effect in Ni50Mn37Sn13 magnetocaloric ribbons. Mater Sci Eng A 2012;534:568e72. nchez Llamazares JL, Sanchez T, Santos JD, Pe rez MJ, Sanchez ML, [28] Sa Hernando B, et al. Martensitic phase transformation in rapidly solidified Mn50Ni40In10 alloy ribbons. Appl Phys Lett 2008;92:012513. nchez Llamazares JL, Hernando B, Prida VM, García C, Gonza lez J, Varga R, [29] Sa et al. Magnetic field influence on the structural transformation in ferromagnetic shape memory alloy Mn50Ni40In10 melt spun ribbons. J Appl Phys 2009;105:07A945.. nchez Llamazares JL, Santos JD, Sa nchez ML, Escoda LI, Suno ~ l JJ, [30] Hernando B, Sa et al. Grain oriented NiMnSn and NiMnIn Heusler alloys ribbons produced by melt spinning: martensitic transformation and magnetic properties. J Magn Magn Mater 2009;321:763e8. nchez LIamazares JL, Prida VM, Baldomir D, Serantes D, IIyn M, [31] Hernando B, Sa et al. Magnetocaloric effect in preferentially textured Mn50Ni40In10 melt spun ribbons. Appl Phys Lett 2009;94:222502. [32] Ren J, Li HW, Yu JK, Feng ST, Zhai QJ, Fu JX, et al. Enhanced magnetocaloric effect in Heusler NieMneSn unidirectional crystal. J Alloy Compd 2015;634: 65e9. [33] Yu JK, Ren J, Li HX, Fu JX, Zhai QJ, Luo ZP, et al. A new approach to grow Heusler NieMneSn unidirectional crystal. J Cryst Growth 2014;402:147e50. [34] Miyamoto T, Nagasako M, Kainuma R. Phase equilibria in the NieMneIn alloy system. J Alloy Compd 2013;549:57e63. [35] Pathak AK, Dubenko I, Stadler S, Ali N. The effect of partial substitution of In by Si on the phase transitions and respective magnetic entropy changes of Ni50Mn35In15 Heusler alloy. J Phys D Appl Phys 2008;41:202004. [36] Ao WQ, Liu FS, Li JQ, Du Y, Liu FL. Isothermal section of the NieMneIn ternary system at 773 K. J Alloy Compd 2015;622:149e54. nchez-Alarcos V, Pe rez-Landaz lez J, Rodríguez[37] Sa abal JI, Recarte V, Lucia I, Ve n JA. Effect of high-temperature quenching on the magnetostructural Velaza transformations and the long-range atomic order of NieMneSn and NieMneSb metamagnetic shape memory alloys. Acta Mater 2013;61(12): 4676e82. [38] Pathak AK, Khan M, Dubenko I, Stadler S, Ali N. Large magnetic entropy change in Ni50Mn50xInx Heusler alloys. Appl Phys Lett 2007;90:262504. [39] Umetsu RY, Kainuma R, Amako Y, Taniguchi Y, Kanomata T, Fukushima K, €ssbauer study on martensite phase in Ni50Mn36.557Fe0.5Sn13 metaet al. Mo magnetic shape memory alloy. Appl Phys Lett 2008;93:042509. [40] Franco V, Bl azquez JS, Ingale B, Conde A. The magnetocaloric effect and magnetic refrigeration near room temperature: materials and models. Annu Rev Mater Res 2012;42:305e42. ~ osa LI, Planes A, Casanova F, Batlle X, Labarta A. Multiscale origin [41] Marcos J, Man of the magnetocaloric effect in NieMneGa shape-memory alloys. Phys Rev B 2003;68:094401.