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Magnetocaloric effect and magnetostrictive deformation in Tb-Dy-Gd-Co-Al with Laves phase structure
Accepted Manuscript Magnetocaloric effect and magnetostrictive deformation in Tb-Dy-Gd-Co-Al with Laves phase structure G.A. Politova, N.Yu. Pankratov, P.Yu. Vanina, A.V. Filimonov, A.I. Rudskoy, G.S. Burkhanov, A.S. Ilyushin, I.S. Tereshina PII: DOI: Reference:
S0304-8853(17)32678-1 https://doi.org/10.1016/j.jmmm.2017.11.016 MAGMA 63356
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Journal of Magnetism and Magnetic Materials
Please cite this article as: G.A. Politova, N.Yu. Pankratov, P.Yu. Vanina, A.V. Filimonov, A.I. Rudskoy, G.S. Burkhanov, A.S. Ilyushin, I.S. Tereshina, Magnetocaloric effect and magnetostrictive deformation in Tb-Dy-GdCo-Al with Laves phase structure, Journal of Magnetism and Magnetic Materials (2017), doi: https://doi.org/ 10.1016/j.jmmm.2017.11.016
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Magnetocaloric effect and magnetostrictive deformation in Tb-Dy-Gd-Co-Al with Laves phase structure G. A. Politovaa,∗, N. Yu. Pankratovb , P. Yu. Vaninac , A. V. Filimonovc , A. I. Rudskoyc , G. S. Burkhanova , A. S. Ilyushinb,d , I. S. Tereshinab a Baikov
Institute of Metallurgy and Materials Science RAS, 119334 Moscow, Russia Moscow State University, Faculty of Physics, 119991 Moscow, Russia c Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia d Complex Research Institute named after Kh. I. Ibragimov RAS, 364906 Groznyi, Russia b Lomonosov
Abstract The influence of partial substitution of Co by Al atoms on the magnetocaloric and magnetostrictive properties of the multicomponent Tb-Dy-Gd-Co compounds with a Laves phase structure was investigated.
The samples were
obtained by arc melting using of high-purity rare-earth metals. The crystal structure of Tb0.2 Dy0.8−x Gdx Co2−y Aly (x = 0.3, 0.4, and 0.5; y = 0 and 0.1) compounds was monitored by powder X-ray diffraction. The magnetostriction and the magnetocaloric effect in external magnetic field up to 12 and 18 kOe, respectively, were studied in wide temperature range. The Curie temperature of Al-content compounds increases by an average of 20 K, while the magnitudes of the magnetocaloric effect and the magnetostriction slightly decrease. Keywords: Rare-earth intermetallic compounds, Laves phase, Magnetostriction, Magnetocaloric effect
1. Introduction The rare earth (R) Laves phases RCo2 with cubic MgCu2 -type structure (C15) [1] exhibit a number of interesting effects such as large magnetovolume effect, significant anisotropic magnetostriction (MS), and large magnetocaloric ∗ Corresponding
author Email address: [email protected] (G. A. Politova)
Preprint submitted to Journal of Magnetism and Magnetic Materials
November 6, 2017
5
effect (MCE) [2–6] in the region of the Curie temperature (TC ). By using both various combinations of rare-earth metals (REM) [7–9] and partial replacement of Co with other 3d-metals [10–13], it is possible to design new functional materials with specific magnetic characteristics. The substitution of larger Al atoms for smaller Co atoms in RCo2 -type compounds [14–17] leads to changes both
10
the unit cell volume and the electronic structure. The present paper focuses on the analysis of the effect of partial substitution of cobalt by Al on the both MCE and MS of the multicomponent (Tb,Dy,Gd)Co2 compounds. The reason for selecting Tb, Dy, and Gd is twofold. First, terbium and dysprosium have opposite sign of the magnetic anisotropy constant
15
K1 [18–20]. Therefore, it affords to obtain an alloy with compensated magnetic anisotropy. Second, the Gd atom has nonorbital magnetic moments and large total spin [21–24], and consequently make no contribution to the total Rsublattice anisotropy that leads to record both large MS and MCE in moderate magnetic filed. Furthermore the maximum of the volume MS and the MCE is
20
placed near the TC [4, 25, 26]. So, the variation of Gd content allows to shift the TC to the room temperature (RT) region [22].
2. Experimental details The multicomponent Tb0.2 Dy0.8−x Gdx Co2−y Aly (x = 0.3, 0.4 and 0.5; y = 0 and 0.1) alloys were prepared by arc-melting high purity elements (Co: 25
99.99 %; Gd, Tb, Dy: 99.95 %) under a purified argon atmosphere. The alloys were remelted (three times) and then annealed at vacuum (at 900 o C for one month) to obtain homogeneous state. The crystal structure was determined by X-ray diffraction (XRD) on Xray diffractometer Supernova (Agilent) using Mo Kα radiation (λ = 0.71073 ˚ A).
30
Single-phase compounds were selected for further investigation. The temperature variation of the diffraction pattern in the range 80-320 K were studied using Oxford Cobra Cryosystem. The data analysis was performed using a FullProf refinement package within R-factors values of 3-5 % for all fitted patterns [27–
2
Figure 1: Temperature dependencies of the lattice parameters (a0 is for the cubic Laves phase √ √ structure, and a 2 and c/ 3 are for the rhombohedral structure) and the unit cell volume of (a) the Tb0.2 Dy0.4 Gd0.4 Co2 and (b) the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compounds.
29]. 35
The magnetostriction were studied by the strain-gauge method on the polycrystalline samples in the temperature range 80-340 K in external fields up to 12 kOe (1.2 T) applied both along and perpendicularly the direction of the strain-gauge direction, that allows to record both longitudinal (λk ) and transverse (λ⊥ ) MS, respectively.
40
The commercial MagEq MMS 901 setup is used for direct MCE measurement over wide temperature range (80-350 K) in magnetic field up to 18 kOe which allows to track the sample temperature change during adiabatic magnetization/demagnetization processes within field sweep rate of 10 kOe/s in both automatic and manual modes. The temperature was detected by a copper-
45
constantan thermocouple junction sandwiched between the two flat sheets of the samples with a size of 2x4x8 mm.
3. Results and discussion Rietveld refinement of the powder XRD patterns showed that the compounds crystallize in the C15-type cubic Laves phase structure (MgCu2 , space 50
group Fd3m) at high temperature, while at low temperature the XRD patterns were fitted within the rhombohedral unit cell model (space group R3m).
3
Fig. 1 shows the dependencies of the unit cell volume V and lattice parameter a on the temperature for the Al-free Tb0.2 Dy0.4 Gd0.4 Co2 and Al-doping Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compounds. As seen from the figure, both the Al55
free and Al-doping compound with x = 0.4 undergoes a structural phase transition from cubic to the rhombohedral phase below 290 K while unit cell volume is continuous dependence with minimum at phase transition temperature. Such temperature behaviour of the lattice parameters and unit cell volume is observed in all investigated compounds and may indicate a structural distortion in the
60
vicinity of the second order phase transition like TC [25, 26, 30, 31]. The Curie temperatures for the Al-doping compounds with x = 0.3, 0.4, and 0.5 are 270, 285, and 315(±5) K, respectively. It is well known [5, 6] that in RCo2 -based compounds at temperatures close to RT such magnetostructural phase transitions can only be of the second order type. The partial substitution of Al for
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Co increases the unit cell volume due to a larger metallic radius of aluminium (rAl = 1.43 ˚ A) as compared to that of cobalt (rCo = 1.25 ˚ A). At temperatures close to TC , the positive contribution due to the stimulation of the phonons and the negative spontaneous magnetostrictive contribution compensate each other, which causes zero values of the thermal expansion coefficient and minimum on
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V (T ) dependence (it is also typical for the invar Fe-Ni alloys) [19, 26]. So, first of all, the changes in the sign and the values of the field-induced MS was studied in wide temperature range for all samples. Fig. 2(a) and (b) show the field dependencies of the longitudinal λk (H) and transverse λ⊥ (H) MS of the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound in temperature range 80-300 K.
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In spite of the fact that these dependencies are complex and non-monotonic the magnetostrictions are positive close to the TC and increase together with the growth of the applied field. The magnetostriction saturation at TC is not observed. It is known that the saturation of MS is observed for the processes of rotation of magnetization vectors [19]. Therefore, the forced magnetostriction
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is responsible for the MS near TC [26]. On the other hand, Fig. 2 (c) and (d) display the temperature dependencies λk (T ) and λ⊥ (T ) for the same compound in selected magnetic fields (from 1.5 4
Figure 2: (a,b) Field and (c,d) temperature dependencies of the longitudinal and transverse magnetostrictions of Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound.
to 12 kOe). In both cases the MS reaches the local positive maximums near TC . It is notice that the shape of λk (T ) and λ⊥ (T ) dependencies above 160 K is 85
typical for the polycrystalline [19, 32]. As a rule, the longitudinal MS is positive at low temperatures and near the TC and the transverse MS is negative at low temperatures and has the positive maximum near the TC [32]. The largest extremum on the temperature dependence of the both longitudinal and transverse MS was found in the temperature range 130-160 K. The tem-
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perature position of extremum depends strongly on the magnitude of the external magnetic field. As far as the lattice parameters of Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 without field show a continual dependence in temperature range 130-160 K (see Fig. 1(b)) and field induced MS undergo a sharp turn (see Fig. 2), so the nature of the extremum is apparently connected with the spin-reorientation transition
95
(SRT). These distinctive features of the λk (T ) and λ⊥ (T ) behaviour are typical for both Al-free and Al-doped compounds. This transition is “pure” magnetic 5
Figure 3: (a) The temperature dependencies of the volume and anisotropic magnetostriction of the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound and (b) the volume magnetostriction for the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds (x = 0.3, 0.4, 0.5, y = 0, 0.1) at H = 12 kOe.
without structural changes and also belongs to second order type [33]. The volume and anisotropic MS of the polycrystalline were found by the relations λω = λk + 2λ⊥ and λanis = 2/3(λk −λ⊥ ). It is seen from Fig. 3(a) that 100
the field induced volume MS reaches the maximum at the TC (λω = 150·10−6 in field of 12 kOe). As expected, the λω near TC increased together with the field as in this case the forced magnetostriction was dominant (the forced MS increases linearly with the field) [25]. In comparison to the λω (T ), λk (T ), and λ⊥ (T ) dependencies the temperature dependence of the anisotropic MS λanis (T ) has
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not any peak at TC . The λanis (T ) reaches the maximum value (λanis = 425·10−6 in field of 12 kOe) at the SRT temperature (TSR = 140 K). Fig. 3(b) shows the temperature dependencies of the volume magnetostriction in the Curie temperature region of all studied compounds. The maximum MS value at TC remains abreast for the Al-free system. It was established that
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partial substitution of cobalt by Al atoms leads to increase of the TC by an average of 20 K and decrease of the volume magnetostriction. On the next step the magnetocaloric effect in the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds (x = 0.3, 0.4, 0.5, y = 0, 0.1) was studied in detail by the direct method in the Curie temperature region. Fig. 4(a) shows the temperature de-
115
pendencies of the adiabatic temperature change (∆Tad ) in the Al-doping com6
Figure 4: The temperature dependencies of the adiabatic temperature change obtained by direct method for the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound at different magnetic field change (a) and for the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds (x = 0.3, 0.4, 0.5, y = 0, 0.1) at ∆H = 18 kOe (b).
pound with x = 0.4 under conditions of applied magnetic field of different values. It is seen that the MCE reaches the maximum value near TC (∆Tad = 1 K) at field change from 0 to 18 kOe. Fig. 4(b) shows the temperature dependencies of the ∆Tad in the range of the Curie temperature for all compounds. It was es120
tablished that the partial substitution of cobalt by aluminium leads to decrease of the MCE. The temperature dependences of ∆Tad (T ) and λω (T ) have a similar shape for both Tb0.2 Dy0.8−x Gdx Co2 and Tb0.2 Dy0.8−x Gdx Co1.9 Al0.1 systems. It should be noticed that the thermodynamic theory is well confirmed subject to the pro-
125
portional of the field induced volume MS and the MCE to the squared magnetization [4, 6, 19, 26]. This proportional provides a direct relationship between the values of λω and ∆Tad close to TC . The correlation of our results with data obtained and analysed earlier [6] for other RCo2 -type compounds is also observed.
130
4. Conclusion The MS and the MCE of the Tb0.2 Dy0.8−x Gdx Co1.9 Al0.1 (x = 0.3, 0.4, and 0.5) compounds were studied in detail and compared with similar phenomena
7
in origin Al-free compounds. All compounds undergo the second order magnetostructural phase transitions like Curie temperatures accompanied by the 135
significant volume MS and the MCE where crystal structure transforms from cubic to the rhombohedral phase due to significant contribution of the spontaneous MS. It was found out that on the increase of concentration of Gd and Al the TC monotonically increases. That is related with an increase of unit cell volume due to Al doping [25] and a rise of 4f-sublattice exchange interaction on
140
substitution by Gd. It was established that the maximum value of volume MS and MCE (near the TC ) remains constant over the RT range, while the content of Gd and Dy is varied in both the Al-substituted and the original Al-free compounds. On the other hand, the volume MS and MCE decrease under Al doping. These facts are important and open up varied opportunities for research and de-
145
velopment of new functional materials based on the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds.
Acknowledgement The work was supported by the RFBR and Moscow city Government according to the research project 15-33-70040 mol a mos. P. Yu. Vanina, A. V. Fil150
imonov and A. I. Rudskoy thank the grant of Ministry of Education and Science of the Russian Federation (# 3.1150.2017/4.6) for financial support. The work was also supported by the RFBR grant # 16-02-00472 (N. Yu. Pankratov).
References [1] E. Gratz, A. S. Markosyan, Physical properties of RCo2 Laves phases, 155
Journal of Physics: Condensed Matter 13 (23) (2001) R385–R413. doi: 10.1088/0953-8984/13/23/202. URL http://stacks.iop.org/0953-8984/13/i=23/a=202 [2] S. Khmelevskyi, P. Mohn, The order of the magnetic phase transitions in RCo2 (R = rare earth) intermetallic compounds, Journal of Physics:
8
160
Condensed Matter 12 (45) (2000) 9453–9464. doi:10.1088/0953-8984/ 12/45/308. URL http://stacks.iop.org/0953-8984/12/i=45/a=308 [3] N. Duc, D. K. Anh, P. Brommer, Metamagnetism, giant magnetoresistance and magnetocaloric effects in RCo2 -based compounds in the vicinity of the
165
Curie temperature, Physica B: Condensed Matter 319 (1-4) (2002) 1–8. doi:10.1016/S0921-4526(02)01099-2. URL
http://www.sciencedirect.com/science/article/pii/
S0921452602010992 [4] A. M. Tishin, Y. I. Spichcin, The magnetocaloric effect and its applications, 170
Institute of Physics Publishing, Bristol and Philadelphia, 2003. [5] K. Gschneidner, Y. Mudryk, V. Pecharsky, On the nature of the magnetocaloric effect of the first-order magnetostructural transition, Scripta Materialia 67 (6) (2012) 572–577, viewpoint Set No. 51: Magnetic Materials for Energy. doi:10.1016/j.scriptamat.2011.12.042.
175
URL
http://www.sciencedirect.com/science/article/pii/
S1359646212000024 [6] I. Tereshina, J. Cwik, E. Tereshina, G. Politova, G. Burkhanov, V. Chzhan, A. Ilyushin, M. Miller, A. Zaleski, K. Nenkov, L. Schultz, Multifunctional phenomena in rare-earth intermetallic compounds with a Laves phase struc180
ture: Giant magnetostriction and magnetocaloric effect, IEEE Trans. Mag. 50 (11) (2014) 2504604. doi:10.1109/tmag.2014.2324636. [7] N. A. de Oliveira, Magnetocaloric effect in (Tb1−z Dyz )Co2 , J. Magn. Magn. Mater. 320 (14) (2008) e150–e152. doi:10.1016/j.jmmm.2008.02.037. URL
185
http://www.sciencedirect.com/science/article/pii/
S0304885308001248 [8] I. Tereshina, G. Politova, E. Tereshina, S. Nikitin, G. Burkhanov, O. Chistyakov, A. Karpenkov, Magnetocaloric and magnetoelastic effects
9
in (Tb0.45 Dy0.55 )1−x Erx Co2 multicomponent compounds, J. Phys.: Conf. Series. 200 (9) (2010) 092012. doi:10.1088/1742-6596/200/9/092012. 190
URL http://stacks.iop.org/1742-6596/200/i=9/a=092012 ` [9] J. Cwik, K. Nenkov, I. S. Tereshina, T. Palewski, The influence of Er substitution on magnetic and magnetocaloric properties of Ho1−x Erx Co2 solid solution, Materials Chemistry and Physics 136 (2) (2012) 492–497. doi:10.1016/j.matchemphys.2012.07.016.
195
URL
http://www.sciencedirect.com/science/article/pii/
S0254058412006530 [10] J. Prokleka, J. Vejpravov, D. Vasylyev, S. Dani, V. Sechovsk, Magnetocaloric phenomena in RE(Co1−x Xx )2 compounds, J. Magn. Magn. Mater. 290 (Part 1) (2005) 676–678, proceedings of the Joint European 200
Magnetic Symposia (JEMS’ 04). doi:10.1016/j.jmmm.2004.11.334. URL
http://www.sciencedirect.com/science/article/pii/
S0304885304015987 [11] M. Anikin, E. Tarasov, N. Kudrevatykh, A. Inishev, M. Semkin, A. Volegov, A. Zinin, Features of magnetic and thermal properties of 205
R(Co1−x Fex )2 (x ≤ 0.16) quasibinary compounds with R=Dy, Ho, Er, J. Magn. Magn. Mater. 418 (Supplement C) (2016) 181–187, peer-reviewed papers from International Conference on Magnetic Materials and Applications. doi:10.1016/j.jmmm.2016.02.082. URL
210
http://www.sciencedirect.com/science/article/pii/
S0304885316301792 [12] I. S. Tereshina, G. A. Politova, E. A. Tereshina, G. S. Burkhanov, O. D. Chistyakov, S. A. Nikitin, Magnetocaloric effect in (Tb,Dy,R)(Co,Fe)2 (R = Ho, Er) multicomponent compounds, J. Phys.: Conf. Series. 266 (1) (2011) 012077. doi:10.1088/1742-6596/266/1/012077.
215
URL http://stacks.iop.org/1742-6596/266/i=1/a=012077 [13] G. Gerasimov, N. V. Mushnikov, A. A. Inishev, P. B. Terentev, V. S. 10
Gaviko, Structure, magnetic and magnetothermal properties of the nonstoichiometric ErCo2 Mnx , J. Alloys Compd. 680 (Supplement C) (2016) 359–365. doi:10.1016/j.jallcom.2016.04.130. 220
URL
http://www.sciencedirect.com/science/article/pii/
S0925838816311069 [14] H. Liu, D. Wang, S. Tang, Q. Cao, T. Tang, B. Gu, Y. Du, The
magnetocaloric
effect
and
magnetic
phase
transitions
in
Dy(Co1−x Alx )2 compounds, J. Alloys Compd. 346 (1) (2002) 314– 225
319. doi:10.1016/S0925-8388(02)00848-4. URL
http://www.sciencedirect.com/science/article/pii/
S0925838802008484 [15] T. Ivanova, S. Nikitin, G. Tskhadadze, Y. Koshkidko, W. Suski, W. Iwasieczko, D. Badurski, Magnetic, transport and magnetocaloric 230
properties in the Laves phase intermetallic Ho(Co1−x Alx )2 compounds,
J. Alloys Compd. 592 (Supplement C) (2014) 271–276.
doi:10.1016/j.jallcom.2013.12.171. URL
http://www.sciencedirect.com/science/article/pii/
S0925838813031629 235
[16] I. S. Tereshina, V. B. Chzhan, E. A. Tereshina, S. Khmelevskyi, G. S. Burkhanov, A. S. Ilyushin, M. A. Paukov, L. Havela, A. Y. Karpenkov, J. Cwik, Y. S. Koshkid’ko, M. Miller, K. Nenkov, L. Schultz, Magnetostructural phase transitions and magnetocaloric effect in Tb-Dy-Ho-Co-Al alloys with a Laves phase structure, J. Appl. Phys. 120 (1) (2016) 013901.
240
doi:10.1063/1.4955047. [17] V. B. Chzhan, E. A. Tereshina, A. B. Mikhailova, G. A. Politova, ` I. S. Tereshina, V. I. Kozlov, J. Cwik, K. Nenkov, O. A. Alekseeva, A. V. Filimonov, Effect of Tb and Al substitution within the rare earth and cobalt sublattices on magnetothermal properties of
245
Dy0.5 Ho0.5 Co2 , J. Magn. Magn. Mater. 432 (Supplement C) (2017) 11
461–465. doi:10.1016/j.jmmm.2017.02.025. URL
http://www.sciencedirect.com/science/article/pii/
S0304885316333613 [18] A. Clark, Chapter 15 Magnetostrictive RFe2 intermetallic compounds, in: 250
K. A. Gschneidner Jr., L. Eyring (Eds.), Alloys and Intermetallics, Vol. 2 of Handbook on the Physics and Chemistry of Rare Earths, Elsevier, 1979, Ch. 15, pp. 231–258. doi:10.1016/S0168-1273(79)02006-7. URL
http://www.sciencedirect.com/science/article/pii/
S0168127379020067 255
[19] K. P. Belov, Magnetostriction Phenomena and Their Technical Application, Nauka, Moscow, 1987, [in russian]. [20] G. S. Burkhanov, I. S. Tereshina, G. A. Politova, O. D. Chistyakov, G. Drulis, A. Zaleski, Magnetocaloric effect in compounds exhibiting gigantic magnetostriction, Doklady Physics 56 (10) (2011) 513–516. doi:
260
10.1134/S1028335811100065. [21] S. A. Nikitin, The magnetic properties of rare earth metals and their alloys, Moscow University Publishers, Moscow, 1989, [in russian]. [22] Z. Gu, B. Zhou, J. Li, W. Ao, G. Cheng, J. Zhao, Magnetocaloric effect of GdCo2−x Alx compounds, Solid State Communications 141 (10) (2007)
265
548–550. doi:10.1016/j.ssc.2006.12.026. URL
http://www.sciencedirect.com/science/article/pii/
S0038109806010969 [23] G. S. Burkhanov, N. B. Kolchugina, E. A. Tereshina, I. S. Tereshina, G. A. Politova, V. B. Chzhan, D. Badurski, O. D. Chistyakov, M. Paukov, 270
H. Drulis, L. Havela, Magnetocaloric properties of distilled gadolinium: Effects of structural inhomogeneity and hydrogen impurity, Applied Physics Letters 104 (24) (2014) 242402. doi:10.1063/1.4883744.
12
[24] E. A. Tereshina, S. Khmelevskyi, G. Politova, T. Kaminskaya, H. Drulis, I. S. Tereshina, Magnetic ordering temperature of nanocrystalline Gd: en275
hancement of magnetic interactions via hydrogenation-induced “negative” pressure, Scientific Reports 6 (2016) 22553. doi:10.1038/srep22553. [25] S. A. Nikitin, I. S. Tereshina, N. Y. Pankratov, E. A. Tereshina, Y. V. Skourski, K. P. Skokov, Y. G. Pastushenkov, Magnetic anisotropy and magnetostriction in a Lu2 Fe17 intermetallic single crystal, Phys. Solid State
280
43 (9) (2001) 1720–1727. doi:10.1134/1.1402229. [26] S. A. Nikitin, N. Y. Pankratov, A. I. Smarzhevskaya, G. A. Politova, Y. G. Pastushenkov, K. P. Skokov, A. del Moral, Giant volume magnetostriction in the Y2 Fe17 single crystal at room temperature, J. Appl. Phys. 117 (19) (2015) 193908. doi:10.1063/1.4919593.
285
[27] R. G. Burkovsky, A. V. Filimonov, A. I. Rudskoy, K. Hirota, M. Matsuura, S. B. Vakhrushev, Diffuse scattering anisotropy and inhomogeneous lattice deformations in the lead magnoniobate relaxor PMN above the Burns temperature, Phys. Rev. B 85 (2012) 094108. doi:10.1103/PhysRevB.85. 094108.
290
URL https://link.aps.org/doi/10.1103/PhysRevB.85.094108 [28] A. A. Naberezhnov, N. Porechnaya, V. Nizhankovskii, A. Filimonov, B. Nacke, Morphology and magnetic properties of ferriferous two-phase sodium borosilicate glasses, The Scientific World Journal 2014 (2014) 320451(7 pages). doi:10.1155/2014/320451.
295
[29] R. G. Burkovsky, D. Andronikova, Y. Bronwald, M. Krisch, K. Roleder, A. Majchrowski, A. V. Filimonov, A. I. Rudskoy, S. B. Vakhrushev, Lattice dynamics in the paraelectric phase of PbHfO3 studied by inelastic x-ray scattering, Journal of Physics: Condensed Matter 27 (2015) 335901. doi: 10.1088/0953-8984/27/33/335901.
300
URL http://stacks.iop.org/0953-8984/27/i=33/a=335901
13
[30] Z. W. Ouyang, F. W. Wang, Q. Hang, W. F. Liu, G. Y. Liu, J. W. Lynn, J. K. Liang, G. H. Rao, Temperature dependent neutron powder diffraction study of the Laves phase compound TbCo2 , J. Alloys Compd. 390 (1) (2005) 21–25. doi:10.1016/j.jallcom.2004.08.028. 305
URL
http://www.sciencedirect.com/science/article/pii/
S0925838804010552 [31] G. A. Politova, V. B. Chzhan, I. S. Tereshina, G. S. Burkhanov, A. A. Manakov, O. A. Alekseeva, A. V. Filimonov, A. S. Ilyushin, Spontaneous and external magnetic field induced magnetostriction in RCo2 310
based multicomponent alloys, Phys. Solid State 57 (12) (2015) 2417–2422. doi:10.1134/S1063783415120288. [32] I. Tereshina, G. Politova, E. Tereshina, J. Cwik, S. Nikitin, O. Chistyakov, A. Karpenkov,
D. Karpenkov,
T. Palewski,
Magnetostriction in
(Tb0.45 Dy0.55 )1−x Erx Co2 (x = 0.1, 0.2): high-field investigation, J. Phys.: 315
Conf. Series. 303 (1) (2011) 012024.
doi:10.1088/1742-6596/303/1/
012024. URL http://stacks.iop.org/1742-6596/303/i=1/a=012024 [33] M. Ilyn, M. I. Bartashevich, A. V. Andreev, E. A. Tereshina, V. Zhukova, A. Zhukov, J. Gonzalez, Magnetocaloric effect in single crystal Nd2 Co7 , J. 320
Appl. Phys. 109 (2011) 083932. doi:10.1063/1.3563583.
14
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Please cite this article as: G.A. Politova, N.Yu. Pankratov, P.Yu. Vanina, A.V. Filimonov, A.I. Rudskoy, G.S. Burkhanov, A.S. Ilyushin, I.S. Tereshina, Magnetocaloric effect and magnetostrictive deformation in Tb-Dy-GdCo-Al with Laves phase structure, Journal of Magnetism and Magnetic Materials (2017), doi: https://doi.org/ 10.1016/j.jmmm.2017.11.016
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Magnetocaloric effect and magnetostrictive deformation in Tb-Dy-Gd-Co-Al with Laves phase structure G. A. Politovaa,∗, N. Yu. Pankratovb , P. Yu. Vaninac , A. V. Filimonovc , A. I. Rudskoyc , G. S. Burkhanova , A. S. Ilyushinb,d , I. S. Tereshinab a Baikov
Institute of Metallurgy and Materials Science RAS, 119334 Moscow, Russia Moscow State University, Faculty of Physics, 119991 Moscow, Russia c Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia d Complex Research Institute named after Kh. I. Ibragimov RAS, 364906 Groznyi, Russia b Lomonosov
Abstract The influence of partial substitution of Co by Al atoms on the magnetocaloric and magnetostrictive properties of the multicomponent Tb-Dy-Gd-Co compounds with a Laves phase structure was investigated.
The samples were
obtained by arc melting using of high-purity rare-earth metals. The crystal structure of Tb0.2 Dy0.8−x Gdx Co2−y Aly (x = 0.3, 0.4, and 0.5; y = 0 and 0.1) compounds was monitored by powder X-ray diffraction. The magnetostriction and the magnetocaloric effect in external magnetic field up to 12 and 18 kOe, respectively, were studied in wide temperature range. The Curie temperature of Al-content compounds increases by an average of 20 K, while the magnitudes of the magnetocaloric effect and the magnetostriction slightly decrease. Keywords: Rare-earth intermetallic compounds, Laves phase, Magnetostriction, Magnetocaloric effect
1. Introduction The rare earth (R) Laves phases RCo2 with cubic MgCu2 -type structure (C15) [1] exhibit a number of interesting effects such as large magnetovolume effect, significant anisotropic magnetostriction (MS), and large magnetocaloric ∗ Corresponding
author Email address: [email protected] (G. A. Politova)
Preprint submitted to Journal of Magnetism and Magnetic Materials
November 6, 2017
5
effect (MCE) [2–6] in the region of the Curie temperature (TC ). By using both various combinations of rare-earth metals (REM) [7–9] and partial replacement of Co with other 3d-metals [10–13], it is possible to design new functional materials with specific magnetic characteristics. The substitution of larger Al atoms for smaller Co atoms in RCo2 -type compounds [14–17] leads to changes both
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the unit cell volume and the electronic structure. The present paper focuses on the analysis of the effect of partial substitution of cobalt by Al on the both MCE and MS of the multicomponent (Tb,Dy,Gd)Co2 compounds. The reason for selecting Tb, Dy, and Gd is twofold. First, terbium and dysprosium have opposite sign of the magnetic anisotropy constant
15
K1 [18–20]. Therefore, it affords to obtain an alloy with compensated magnetic anisotropy. Second, the Gd atom has nonorbital magnetic moments and large total spin [21–24], and consequently make no contribution to the total Rsublattice anisotropy that leads to record both large MS and MCE in moderate magnetic filed. Furthermore the maximum of the volume MS and the MCE is
20
placed near the TC [4, 25, 26]. So, the variation of Gd content allows to shift the TC to the room temperature (RT) region [22].
2. Experimental details The multicomponent Tb0.2 Dy0.8−x Gdx Co2−y Aly (x = 0.3, 0.4 and 0.5; y = 0 and 0.1) alloys were prepared by arc-melting high purity elements (Co: 25
99.99 %; Gd, Tb, Dy: 99.95 %) under a purified argon atmosphere. The alloys were remelted (three times) and then annealed at vacuum (at 900 o C for one month) to obtain homogeneous state. The crystal structure was determined by X-ray diffraction (XRD) on Xray diffractometer Supernova (Agilent) using Mo Kα radiation (λ = 0.71073 ˚ A).
30
Single-phase compounds were selected for further investigation. The temperature variation of the diffraction pattern in the range 80-320 K were studied using Oxford Cobra Cryosystem. The data analysis was performed using a FullProf refinement package within R-factors values of 3-5 % for all fitted patterns [27–
2
Figure 1: Temperature dependencies of the lattice parameters (a0 is for the cubic Laves phase √ √ structure, and a 2 and c/ 3 are for the rhombohedral structure) and the unit cell volume of (a) the Tb0.2 Dy0.4 Gd0.4 Co2 and (b) the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compounds.
29]. 35
The magnetostriction were studied by the strain-gauge method on the polycrystalline samples in the temperature range 80-340 K in external fields up to 12 kOe (1.2 T) applied both along and perpendicularly the direction of the strain-gauge direction, that allows to record both longitudinal (λk ) and transverse (λ⊥ ) MS, respectively.
40
The commercial MagEq MMS 901 setup is used for direct MCE measurement over wide temperature range (80-350 K) in magnetic field up to 18 kOe which allows to track the sample temperature change during adiabatic magnetization/demagnetization processes within field sweep rate of 10 kOe/s in both automatic and manual modes. The temperature was detected by a copper-
45
constantan thermocouple junction sandwiched between the two flat sheets of the samples with a size of 2x4x8 mm.
3. Results and discussion Rietveld refinement of the powder XRD patterns showed that the compounds crystallize in the C15-type cubic Laves phase structure (MgCu2 , space 50
group Fd3m) at high temperature, while at low temperature the XRD patterns were fitted within the rhombohedral unit cell model (space group R3m).
3
Fig. 1 shows the dependencies of the unit cell volume V and lattice parameter a on the temperature for the Al-free Tb0.2 Dy0.4 Gd0.4 Co2 and Al-doping Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compounds. As seen from the figure, both the Al55
free and Al-doping compound with x = 0.4 undergoes a structural phase transition from cubic to the rhombohedral phase below 290 K while unit cell volume is continuous dependence with minimum at phase transition temperature. Such temperature behaviour of the lattice parameters and unit cell volume is observed in all investigated compounds and may indicate a structural distortion in the
60
vicinity of the second order phase transition like TC [25, 26, 30, 31]. The Curie temperatures for the Al-doping compounds with x = 0.3, 0.4, and 0.5 are 270, 285, and 315(±5) K, respectively. It is well known [5, 6] that in RCo2 -based compounds at temperatures close to RT such magnetostructural phase transitions can only be of the second order type. The partial substitution of Al for
65
Co increases the unit cell volume due to a larger metallic radius of aluminium (rAl = 1.43 ˚ A) as compared to that of cobalt (rCo = 1.25 ˚ A). At temperatures close to TC , the positive contribution due to the stimulation of the phonons and the negative spontaneous magnetostrictive contribution compensate each other, which causes zero values of the thermal expansion coefficient and minimum on
70
V (T ) dependence (it is also typical for the invar Fe-Ni alloys) [19, 26]. So, first of all, the changes in the sign and the values of the field-induced MS was studied in wide temperature range for all samples. Fig. 2(a) and (b) show the field dependencies of the longitudinal λk (H) and transverse λ⊥ (H) MS of the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound in temperature range 80-300 K.
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In spite of the fact that these dependencies are complex and non-monotonic the magnetostrictions are positive close to the TC and increase together with the growth of the applied field. The magnetostriction saturation at TC is not observed. It is known that the saturation of MS is observed for the processes of rotation of magnetization vectors [19]. Therefore, the forced magnetostriction
80
is responsible for the MS near TC [26]. On the other hand, Fig. 2 (c) and (d) display the temperature dependencies λk (T ) and λ⊥ (T ) for the same compound in selected magnetic fields (from 1.5 4
Figure 2: (a,b) Field and (c,d) temperature dependencies of the longitudinal and transverse magnetostrictions of Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound.
to 12 kOe). In both cases the MS reaches the local positive maximums near TC . It is notice that the shape of λk (T ) and λ⊥ (T ) dependencies above 160 K is 85
typical for the polycrystalline [19, 32]. As a rule, the longitudinal MS is positive at low temperatures and near the TC and the transverse MS is negative at low temperatures and has the positive maximum near the TC [32]. The largest extremum on the temperature dependence of the both longitudinal and transverse MS was found in the temperature range 130-160 K. The tem-
90
perature position of extremum depends strongly on the magnitude of the external magnetic field. As far as the lattice parameters of Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 without field show a continual dependence in temperature range 130-160 K (see Fig. 1(b)) and field induced MS undergo a sharp turn (see Fig. 2), so the nature of the extremum is apparently connected with the spin-reorientation transition
95
(SRT). These distinctive features of the λk (T ) and λ⊥ (T ) behaviour are typical for both Al-free and Al-doped compounds. This transition is “pure” magnetic 5
Figure 3: (a) The temperature dependencies of the volume and anisotropic magnetostriction of the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound and (b) the volume magnetostriction for the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds (x = 0.3, 0.4, 0.5, y = 0, 0.1) at H = 12 kOe.
without structural changes and also belongs to second order type [33]. The volume and anisotropic MS of the polycrystalline were found by the relations λω = λk + 2λ⊥ and λanis = 2/3(λk −λ⊥ ). It is seen from Fig. 3(a) that 100
the field induced volume MS reaches the maximum at the TC (λω = 150·10−6 in field of 12 kOe). As expected, the λω near TC increased together with the field as in this case the forced magnetostriction was dominant (the forced MS increases linearly with the field) [25]. In comparison to the λω (T ), λk (T ), and λ⊥ (T ) dependencies the temperature dependence of the anisotropic MS λanis (T ) has
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not any peak at TC . The λanis (T ) reaches the maximum value (λanis = 425·10−6 in field of 12 kOe) at the SRT temperature (TSR = 140 K). Fig. 3(b) shows the temperature dependencies of the volume magnetostriction in the Curie temperature region of all studied compounds. The maximum MS value at TC remains abreast for the Al-free system. It was established that
110
partial substitution of cobalt by Al atoms leads to increase of the TC by an average of 20 K and decrease of the volume magnetostriction. On the next step the magnetocaloric effect in the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds (x = 0.3, 0.4, 0.5, y = 0, 0.1) was studied in detail by the direct method in the Curie temperature region. Fig. 4(a) shows the temperature de-
115
pendencies of the adiabatic temperature change (∆Tad ) in the Al-doping com6
Figure 4: The temperature dependencies of the adiabatic temperature change obtained by direct method for the Tb0.2 Dy0.4 Gd0.4 Co1.9 Al0.1 compound at different magnetic field change (a) and for the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds (x = 0.3, 0.4, 0.5, y = 0, 0.1) at ∆H = 18 kOe (b).
pound with x = 0.4 under conditions of applied magnetic field of different values. It is seen that the MCE reaches the maximum value near TC (∆Tad = 1 K) at field change from 0 to 18 kOe. Fig. 4(b) shows the temperature dependencies of the ∆Tad in the range of the Curie temperature for all compounds. It was es120
tablished that the partial substitution of cobalt by aluminium leads to decrease of the MCE. The temperature dependences of ∆Tad (T ) and λω (T ) have a similar shape for both Tb0.2 Dy0.8−x Gdx Co2 and Tb0.2 Dy0.8−x Gdx Co1.9 Al0.1 systems. It should be noticed that the thermodynamic theory is well confirmed subject to the pro-
125
portional of the field induced volume MS and the MCE to the squared magnetization [4, 6, 19, 26]. This proportional provides a direct relationship between the values of λω and ∆Tad close to TC . The correlation of our results with data obtained and analysed earlier [6] for other RCo2 -type compounds is also observed.
130
4. Conclusion The MS and the MCE of the Tb0.2 Dy0.8−x Gdx Co1.9 Al0.1 (x = 0.3, 0.4, and 0.5) compounds were studied in detail and compared with similar phenomena
7
in origin Al-free compounds. All compounds undergo the second order magnetostructural phase transitions like Curie temperatures accompanied by the 135
significant volume MS and the MCE where crystal structure transforms from cubic to the rhombohedral phase due to significant contribution of the spontaneous MS. It was found out that on the increase of concentration of Gd and Al the TC monotonically increases. That is related with an increase of unit cell volume due to Al doping [25] and a rise of 4f-sublattice exchange interaction on
140
substitution by Gd. It was established that the maximum value of volume MS and MCE (near the TC ) remains constant over the RT range, while the content of Gd and Dy is varied in both the Al-substituted and the original Al-free compounds. On the other hand, the volume MS and MCE decrease under Al doping. These facts are important and open up varied opportunities for research and de-
145
velopment of new functional materials based on the Tb0.2 Dy0.8−x Gdx Co2−y Aly compounds.
Acknowledgement The work was supported by the RFBR and Moscow city Government according to the research project 15-33-70040 mol a mos. P. Yu. Vanina, A. V. Fil150
imonov and A. I. Rudskoy thank the grant of Ministry of Education and Science of the Russian Federation (# 3.1150.2017/4.6) for financial support. The work was also supported by the RFBR grant # 16-02-00472 (N. Yu. Pankratov).
References [1] E. Gratz, A. S. Markosyan, Physical properties of RCo2 Laves phases, 155
Journal of Physics: Condensed Matter 13 (23) (2001) R385–R413. doi: 10.1088/0953-8984/13/23/202. URL http://stacks.iop.org/0953-8984/13/i=23/a=202 [2] S. Khmelevskyi, P. Mohn, The order of the magnetic phase transitions in RCo2 (R = rare earth) intermetallic compounds, Journal of Physics:
8
160
Condensed Matter 12 (45) (2000) 9453–9464. doi:10.1088/0953-8984/ 12/45/308. URL http://stacks.iop.org/0953-8984/12/i=45/a=308 [3] N. Duc, D. K. Anh, P. Brommer, Metamagnetism, giant magnetoresistance and magnetocaloric effects in RCo2 -based compounds in the vicinity of the
165
Curie temperature, Physica B: Condensed Matter 319 (1-4) (2002) 1–8. doi:10.1016/S0921-4526(02)01099-2. URL
http://www.sciencedirect.com/science/article/pii/
S0921452602010992 [4] A. M. Tishin, Y. I. Spichcin, The magnetocaloric effect and its applications, 170
Institute of Physics Publishing, Bristol and Philadelphia, 2003. [5] K. Gschneidner, Y. Mudryk, V. Pecharsky, On the nature of the magnetocaloric effect of the first-order magnetostructural transition, Scripta Materialia 67 (6) (2012) 572–577, viewpoint Set No. 51: Magnetic Materials for Energy. doi:10.1016/j.scriptamat.2011.12.042.
175
URL
http://www.sciencedirect.com/science/article/pii/
S1359646212000024 [6] I. Tereshina, J. Cwik, E. Tereshina, G. Politova, G. Burkhanov, V. Chzhan, A. Ilyushin, M. Miller, A. Zaleski, K. Nenkov, L. Schultz, Multifunctional phenomena in rare-earth intermetallic compounds with a Laves phase struc180
ture: Giant magnetostriction and magnetocaloric effect, IEEE Trans. Mag. 50 (11) (2014) 2504604. doi:10.1109/tmag.2014.2324636. [7] N. A. de Oliveira, Magnetocaloric effect in (Tb1−z Dyz )Co2 , J. Magn. Magn. Mater. 320 (14) (2008) e150–e152. doi:10.1016/j.jmmm.2008.02.037. URL
185
http://www.sciencedirect.com/science/article/pii/
S0304885308001248 [8] I. Tereshina, G. Politova, E. Tereshina, S. Nikitin, G. Burkhanov, O. Chistyakov, A. Karpenkov, Magnetocaloric and magnetoelastic effects
9
in (Tb0.45 Dy0.55 )1−x Erx Co2 multicomponent compounds, J. Phys.: Conf. Series. 200 (9) (2010) 092012. doi:10.1088/1742-6596/200/9/092012. 190
URL http://stacks.iop.org/1742-6596/200/i=9/a=092012 ` [9] J. Cwik, K. Nenkov, I. S. Tereshina, T. Palewski, The influence of Er substitution on magnetic and magnetocaloric properties of Ho1−x Erx Co2 solid solution, Materials Chemistry and Physics 136 (2) (2012) 492–497. doi:10.1016/j.matchemphys.2012.07.016.
195
URL
http://www.sciencedirect.com/science/article/pii/
S0254058412006530 [10] J. Prokleka, J. Vejpravov, D. Vasylyev, S. Dani, V. Sechovsk, Magnetocaloric phenomena in RE(Co1−x Xx )2 compounds, J. Magn. Magn. Mater. 290 (Part 1) (2005) 676–678, proceedings of the Joint European 200
Magnetic Symposia (JEMS’ 04). doi:10.1016/j.jmmm.2004.11.334. URL
http://www.sciencedirect.com/science/article/pii/
S0304885304015987 [11] M. Anikin, E. Tarasov, N. Kudrevatykh, A. Inishev, M. Semkin, A. Volegov, A. Zinin, Features of magnetic and thermal properties of 205
R(Co1−x Fex )2 (x ≤ 0.16) quasibinary compounds with R=Dy, Ho, Er, J. Magn. Magn. Mater. 418 (Supplement C) (2016) 181–187, peer-reviewed papers from International Conference on Magnetic Materials and Applications. doi:10.1016/j.jmmm.2016.02.082. URL
210
http://www.sciencedirect.com/science/article/pii/
S0304885316301792 [12] I. S. Tereshina, G. A. Politova, E. A. Tereshina, G. S. Burkhanov, O. D. Chistyakov, S. A. Nikitin, Magnetocaloric effect in (Tb,Dy,R)(Co,Fe)2 (R = Ho, Er) multicomponent compounds, J. Phys.: Conf. Series. 266 (1) (2011) 012077. doi:10.1088/1742-6596/266/1/012077.
215
URL http://stacks.iop.org/1742-6596/266/i=1/a=012077 [13] G. Gerasimov, N. V. Mushnikov, A. A. Inishev, P. B. Terentev, V. S. 10
Gaviko, Structure, magnetic and magnetothermal properties of the nonstoichiometric ErCo2 Mnx , J. Alloys Compd. 680 (Supplement C) (2016) 359–365. doi:10.1016/j.jallcom.2016.04.130. 220
URL
http://www.sciencedirect.com/science/article/pii/
S0925838816311069 [14] H. Liu, D. Wang, S. Tang, Q. Cao, T. Tang, B. Gu, Y. Du, The
magnetocaloric
effect
and
magnetic
phase
transitions
in
Dy(Co1−x Alx )2 compounds, J. Alloys Compd. 346 (1) (2002) 314– 225
319. doi:10.1016/S0925-8388(02)00848-4. URL
http://www.sciencedirect.com/science/article/pii/
S0925838802008484 [15] T. Ivanova, S. Nikitin, G. Tskhadadze, Y. Koshkidko, W. Suski, W. Iwasieczko, D. Badurski, Magnetic, transport and magnetocaloric 230
properties in the Laves phase intermetallic Ho(Co1−x Alx )2 compounds,
J. Alloys Compd. 592 (Supplement C) (2014) 271–276.
doi:10.1016/j.jallcom.2013.12.171. URL
http://www.sciencedirect.com/science/article/pii/
S0925838813031629 235
[16] I. S. Tereshina, V. B. Chzhan, E. A. Tereshina, S. Khmelevskyi, G. S. Burkhanov, A. S. Ilyushin, M. A. Paukov, L. Havela, A. Y. Karpenkov, J. Cwik, Y. S. Koshkid’ko, M. Miller, K. Nenkov, L. Schultz, Magnetostructural phase transitions and magnetocaloric effect in Tb-Dy-Ho-Co-Al alloys with a Laves phase structure, J. Appl. Phys. 120 (1) (2016) 013901.
240
doi:10.1063/1.4955047. [17] V. B. Chzhan, E. A. Tereshina, A. B. Mikhailova, G. A. Politova, ` I. S. Tereshina, V. I. Kozlov, J. Cwik, K. Nenkov, O. A. Alekseeva, A. V. Filimonov, Effect of Tb and Al substitution within the rare earth and cobalt sublattices on magnetothermal properties of
245
Dy0.5 Ho0.5 Co2 , J. Magn. Magn. Mater. 432 (Supplement C) (2017) 11
461–465. doi:10.1016/j.jmmm.2017.02.025. URL
http://www.sciencedirect.com/science/article/pii/
S0304885316333613 [18] A. Clark, Chapter 15 Magnetostrictive RFe2 intermetallic compounds, in: 250
K. A. Gschneidner Jr., L. Eyring (Eds.), Alloys and Intermetallics, Vol. 2 of Handbook on the Physics and Chemistry of Rare Earths, Elsevier, 1979, Ch. 15, pp. 231–258. doi:10.1016/S0168-1273(79)02006-7. URL
http://www.sciencedirect.com/science/article/pii/
S0168127379020067 255
[19] K. P. Belov, Magnetostriction Phenomena and Their Technical Application, Nauka, Moscow, 1987, [in russian]. [20] G. S. Burkhanov, I. S. Tereshina, G. A. Politova, O. D. Chistyakov, G. Drulis, A. Zaleski, Magnetocaloric effect in compounds exhibiting gigantic magnetostriction, Doklady Physics 56 (10) (2011) 513–516. doi:
260
10.1134/S1028335811100065. [21] S. A. Nikitin, The magnetic properties of rare earth metals and their alloys, Moscow University Publishers, Moscow, 1989, [in russian]. [22] Z. Gu, B. Zhou, J. Li, W. Ao, G. Cheng, J. Zhao, Magnetocaloric effect of GdCo2−x Alx compounds, Solid State Communications 141 (10) (2007)
265
548–550. doi:10.1016/j.ssc.2006.12.026. URL
http://www.sciencedirect.com/science/article/pii/
S0038109806010969 [23] G. S. Burkhanov, N. B. Kolchugina, E. A. Tereshina, I. S. Tereshina, G. A. Politova, V. B. Chzhan, D. Badurski, O. D. Chistyakov, M. Paukov, 270
H. Drulis, L. Havela, Magnetocaloric properties of distilled gadolinium: Effects of structural inhomogeneity and hydrogen impurity, Applied Physics Letters 104 (24) (2014) 242402. doi:10.1063/1.4883744.
12
[24] E. A. Tereshina, S. Khmelevskyi, G. Politova, T. Kaminskaya, H. Drulis, I. S. Tereshina, Magnetic ordering temperature of nanocrystalline Gd: en275
hancement of magnetic interactions via hydrogenation-induced “negative” pressure, Scientific Reports 6 (2016) 22553. doi:10.1038/srep22553. [25] S. A. Nikitin, I. S. Tereshina, N. Y. Pankratov, E. A. Tereshina, Y. V. Skourski, K. P. Skokov, Y. G. Pastushenkov, Magnetic anisotropy and magnetostriction in a Lu2 Fe17 intermetallic single crystal, Phys. Solid State
280
43 (9) (2001) 1720–1727. doi:10.1134/1.1402229. [26] S. A. Nikitin, N. Y. Pankratov, A. I. Smarzhevskaya, G. A. Politova, Y. G. Pastushenkov, K. P. Skokov, A. del Moral, Giant volume magnetostriction in the Y2 Fe17 single crystal at room temperature, J. Appl. Phys. 117 (19) (2015) 193908. doi:10.1063/1.4919593.
285
[27] R. G. Burkovsky, A. V. Filimonov, A. I. Rudskoy, K. Hirota, M. Matsuura, S. B. Vakhrushev, Diffuse scattering anisotropy and inhomogeneous lattice deformations in the lead magnoniobate relaxor PMN above the Burns temperature, Phys. Rev. B 85 (2012) 094108. doi:10.1103/PhysRevB.85. 094108.
290
URL https://link.aps.org/doi/10.1103/PhysRevB.85.094108 [28] A. A. Naberezhnov, N. Porechnaya, V. Nizhankovskii, A. Filimonov, B. Nacke, Morphology and magnetic properties of ferriferous two-phase sodium borosilicate glasses, The Scientific World Journal 2014 (2014) 320451(7 pages). doi:10.1155/2014/320451.
295
[29] R. G. Burkovsky, D. Andronikova, Y. Bronwald, M. Krisch, K. Roleder, A. Majchrowski, A. V. Filimonov, A. I. Rudskoy, S. B. Vakhrushev, Lattice dynamics in the paraelectric phase of PbHfO3 studied by inelastic x-ray scattering, Journal of Physics: Condensed Matter 27 (2015) 335901. doi: 10.1088/0953-8984/27/33/335901.
300
URL http://stacks.iop.org/0953-8984/27/i=33/a=335901
13
[30] Z. W. Ouyang, F. W. Wang, Q. Hang, W. F. Liu, G. Y. Liu, J. W. Lynn, J. K. Liang, G. H. Rao, Temperature dependent neutron powder diffraction study of the Laves phase compound TbCo2 , J. Alloys Compd. 390 (1) (2005) 21–25. doi:10.1016/j.jallcom.2004.08.028. 305
URL
http://www.sciencedirect.com/science/article/pii/
S0925838804010552 [31] G. A. Politova, V. B. Chzhan, I. S. Tereshina, G. S. Burkhanov, A. A. Manakov, O. A. Alekseeva, A. V. Filimonov, A. S. Ilyushin, Spontaneous and external magnetic field induced magnetostriction in RCo2 310
based multicomponent alloys, Phys. Solid State 57 (12) (2015) 2417–2422. doi:10.1134/S1063783415120288. [32] I. Tereshina, G. Politova, E. Tereshina, J. Cwik, S. Nikitin, O. Chistyakov, A. Karpenkov,
D. Karpenkov,
T. Palewski,
Magnetostriction in
(Tb0.45 Dy0.55 )1−x Erx Co2 (x = 0.1, 0.2): high-field investigation, J. Phys.: 315
Conf. Series. 303 (1) (2011) 012024.
doi:10.1088/1742-6596/303/1/
012024. URL http://stacks.iop.org/1742-6596/303/i=1/a=012024 [33] M. Ilyn, M. I. Bartashevich, A. V. Andreev, E. A. Tereshina, V. Zhukova, A. Zhukov, J. Gonzalez, Magnetocaloric effect in single crystal Nd2 Co7 , J. 320
Appl. Phys. 109 (2011) 083932. doi:10.1063/1.3563583.
14