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Structural, magnetic and magnetocaloric properties of La0.65Sr0.35V0.1Mn0.9O3 perovskite
Materials Research Bulletin 47 (2012) 2977–2979
Contents lists available at SciVerse ScienceDirect
Materials Research Bulletin journal homepage: www.elsevier.com/locate/matresbu
Structural, magnetic and magnetocaloric properties of La0.65Sr0.35V0.1Mn0.9O3 perovskite M.S. Anwar, Shalendra Kumar, Faheem Ahmed, Nishat Arshi, Bon Heun Koo * School of Nano and Advanced Materials Engineering, Changwon National University, Changwon, Gyeongnam 641-773, South Korea
A R T I C L E I N F O
A B S T R A C T
Article history: Available online 26 April 2012
A new complex magnetic material La0.65Sr0.35V0.1Mn0.9O3, suitable for the magnetic refrigeration, has been investigated. X-ray diffraction result showed that this compound had rhombohedral structure. The substitution of manganese with V leads to a decrease in the Curie temperature, TC from 378 K to 353 K. Using Arrott plots; it was found that the phase transition for this compound is of the second-order. The magnetocaloric study exposed a quite large value of the magnetic entropy change 1.56 J/kg K and the relative cooling power value of 67 J/kg at magnetic field variation of 1 T. ß 2012 Elsevier Ltd. All rights reserved.
Keywords: A. Inorganic compounds C. X-ray diffraction D. Magnetic properties
1. Introduction Exploration of properties of inorganic material has been a longstanding goal in the development of functional materials [1–3]. There exists a close relationship among structure, morphology and property [4–7]. Extensive studies have been devoted to understanding formation mechanism from both theoretical and experimental views in order to synthesize better functional materials [8– 11]. In last decade, magnetic refrigeration is becoming promising technology to replace the conventional gas compression–expansion technique. So, increasing attention has been paid to find magnetic refrigerant that can operate near room temperature [12]. The MCE manifests as the isothermal magnetic entropy change or the adiabatic temperature change of a magnetic material when exposed to a varying magnetic field. In general, two prerequisites are necessary for inducing large MCE. One is associated with a large enough spontaneous magnetization, while the other is associated with an abrupt drop of magnetization at TC [13]. Therefore, samples exhibiting the second order magnetic phase transition are expected to show a reduced magnetic entropy change and the peak expands with the enhancement of disorder. Compared with first-order materials, second-order ones can have comparable or even larger relative cooling power (RCP), although they sometimes exhibit relatively low values of magnetic entropy change, DSM. Moreover, the absence of magnetic and thermal hysteresis are also promising features of the materials of this kind. It is therefore of significance to search for efficient magnetic refrigerants with the second-order characters.
* Corresponding author. Tel.: +82 55 264 5431; fax: +82 55 262 6486. E-mail addresses: [email protected], shafi[email protected] (B.H. Koo). 0025-5408/$ – see front matter ß 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.materresbull.2012.04.135
In this work, we present the structural and magnetocaloric properties of La0.65Sr0.35V0.1Mn0.9O3 compound. This compound belongs to the family of La1xSrxMnO3, perovskites, for which we observed a quite large value of the magnetic entropy change with the RCP value of 67 J/kg at magnetic field variation of 1 T.
2. Experimental details Ceramic samples with the nominal composition of La0.65Sr0.35MnO3 and La0.65Sr0.35V0.1Mn0.9O3 were synthesized by conventional solid-state ceramics route. The phase purity and structure of the sample were analyzed using an X-ray diffractometer (Rigaku Mini-Flex II). Magnetization measurements were performed using a quantum design vibrating sample magnetometer PPMS-6000 VSM. The magnetocaloric effect in terms of isothermal magnetic entropy change was calculated by using following equation [14]: DSM ðT; MÞ ¼
X M i M iþ2 DH i T iþ2 T i
(1)
where Mi and Mi+1 are the experimental values of the magnetization at Ti and Ti+1, respectively under a magnetic field Hi. The relative cooling power (RCP) have been calculated using the relation [14] @T SWHM RCP ðSÞ ¼ DSmax M
(2)
is the maximum magnetic entropy change and where DSmax M @TFWHM is the full width at half maximum of the magnetic entropy change curve.
M.S. Anwar et al. / Materials Research Bulletin 47 (2012) 2977–2979
2978
Fig. 1. X-ray diffraction pattern La0.65Sr0.35V0.1Mn0.9O3 compounds.
of
(a)
La0.65Sr0.35MnO3
and
(b)
3. Results and discussion Fig. 3. H/M versus M2 isotherms for La0.65Sr0.35V0.1Mn0.9O3 compound. Inset shows the isothermal magnetization curves (M–H) measured at different temperatures around TC.
The X-ray diffraction pattern of the La0.65Sr0.35V0.1Mn0.9O3 (LSVMO) compound is shown in Fig. 1. The XRD pattern indicates that LSVMO compound exhibits the polycrystalline behavior with the maximum intensity for the (1 0 4) reflection. All the reflections indexed to rhombohedral structure with R3c space group using POWDER-X software with the lattice parameters a = b = 5.5142 A˚ and c = 13.2779 A˚. No impurity peaks are observed in the pattern indicating the single phase formation of LSVMO compound. For comparison, standard XRD pattern of La0.65Sr0.35MnO3 (LSMO) is also plotted. Magnetization measurements as a function of temperature showed that our synthesized LSVMO compound exhibit a sharp ferromagnetic to paramagnetic (FM–PM) transition with increasing temperature (Fig. 2). The Curie temperature, TC is determined by two different methods: (a) determination of minimum of the derivative dM/dT of the M–T curve (not shown here), (b) by linear fitting of the Curie Weiss Law [15] in the paramagnetic region as shown in the inset of Fig. 2. The as obtained values of TC are 353 K and 378 K for LSVMO and LSMO compound, respectively. The lowering of TC for LSVMO compound is attributed to the disorder in the compound created by V doping. Since, V can be in any of its three valence states (V3+, V4+, V5+) in the LSVMO compound. But, in the view of charge neutrality and ionic radius (V4+ has a very similar ionic radius compared to that of Mn3+ and Mn4+), V4+ is expected to shift the average valence state of Mn toward to Mn3+,
which also causes a deformation in the Mn3+–O–Mn4+ network and a decrease in TC. The isothermal magnetization for LSVMO compound obtained at different temperatures is shown in Fig. 3 (inset). Below TC, magnetization increases sharply with the applied magnetic field for H < 5000 Oe. The saturation magnetization shifts to higher value of magnetic field with the decreasing temperature, which confirms the FM behavior of our sample at low temperature. In order to get a deeper insight of the type of magnetic phase transition, we derive the Arrott plots (H/M vs. M2) from M–H plots and the results are shown in Fig. 3. The second order magnetic phase transition behavior occurs because of the positive slope in the high magnetic field regions for the LSVMO compound [16]. The evolution of magnetization obtained at different temperatures for LSVMO compound reveals a strong variation of magnetization around the TC (Fig. 3). It indicates that there is a possible large magnetic entropy change associated with the FM– PM transition temperature, occurring at TC. In order to investigate this idea, we have calculated the magnetic entropy change using Eq. (1). The magnetic entropy change data as a function of temperature at various applied magnetic fields for the LSVMO compound are plotted in Fig. 4. The maximum of the magnetic
Fig. 2. Temperature dependence of magnetization for (a) La0.65Sr0.35MnO3 and (b) La0.65Sr0.35V0.1Mn0.9O3 compounds at a magnetic field of 0.5 T. The inset is the plot of Curie Weiss Law vs. temperature.
Fig. 4. Magnetic entropy change of La0.65Sr0.35V0.1Mn0.9O3 compound at different versus applied magnetic fields as a function of temperature. The inset is the DSmax M applied magnetic field.
M.S. Anwar et al. / Materials Research Bulletin 47 (2012) 2977–2979 Table 1 Comparison of reported values of the maximum magnetic entropy change occurring at the Curie temperature and a magnetic field change (DH), for various perovskite manganites and gadolinium metal. Composition
TC (K)
DT (T)
DSmax (J/kg K)
RCP (J/kg)
References
Gd La0.7Sr0.3Mn0.8Cr0.2O3 La0.67Sr0.33MnO3 La0.75Sr0.25MnO3 La0.65Sr0.35MnO3 La0.65Sr0.35V0.1Mn0.9O3
293 286 348 340 378 353
1 2 5 1.5 1 1
3.25 1.20 1.69 1.5 0.99 1.56
– 59 211 65 40 67
[17] [18] [14] [19] Our work Our work
2979
change of La0.65Sr 0.35MnO3 compound (inset of Fig. 5). Around reaches a maximum value of about 0.99 J/kg K 376 K, the DSmax M upon the magnetic field variation of 1 T. The most important factor for selecting magnetic refrigerants is based on the cooling power per unit volume, namely, the relative cooling power (RCP). The material with a larger RCP value usually represents a better magnetocaloric substance due to its high cooling efficiency. RCP values for the LSVMO compound exhibits a linear rise with increasing field, as shown in Fig. 5. From Fig. 5 we also conclude and RCP for the LSVMO compound are that the values of DSmax M greater than those of LSMO. As a result, the La0.65Sr0.35V0.1Mn0.9O3 (LSVMO) compound can be used as potential magnetic refrigerant. 4. Conclusions Synthesis, structural and magnetic characterization of La0.65Sr0.35V0.1Mn0.9O3 compound were performed. X-ray analyses reveal that this material crystallizes in a rhombohedral structure with R3c space group. The V doping leads to the change in Mn–O bond length and Mn–O–Mn bond angle, consequently, the Curie temperature decreased. The obtained compound exhibits a large MCE, which can be attributed to an abrupt magnetization change due to the phase transition near TC. The Arrott plots reveal that the phase transition for this compound is of the second-order and the maximum change in magnetic entropy reaches 1.56 J/kg K in a magnetic field variation of 1 T. The RCP is relatively large; it is about 67 J/kg at magnetic field of 1 T. These results indicate that La0.65Sr0.35V0.1Mn0.9O3 compound is a good candidate as potential magnetic refrigerant with sufficient performance.
Fig. 5. Relative cooling power values versus applied magnetic field for La0.65Sr0.35V0.1Mn0.9O3 compound, inset shows the comparison of magnetic entropy change of La0.65Sr0.35MnO3 and La0.65Sr0.35V0.1Mn0.9O3 compounds.
entropy changes is obtained around 350 K. This temperature is near the Curie temperature of the sample (TC = 353 K). We can see from Fig. 4 that the magnetic entropy change depends on the applied magnetic field change. The larger the magnetic field is, the bigger the magnetic entropy change shall be. The maximum of the upon the applied magnetic field magnetic entropy change DSmax M changes (DH) of 1 and 4 T are about 1.56 and 4.33 J/kg K, exhibits a linear rise with increasing field respectively. DSmax M as shown in the inset of Fig. 4, which indicates much larger entropy change to be expected at higher magnetic field, signifying the effect of spin–lattice coupling associated to changes in the magnetic ordering process in the LSVMO compound [12]. With the observation of large magnetic entropy change and the fact that a strong spin–lattice coupling exists in perovskite manganites, a conclusion can be drawn that a strong spin–lattice coupling in the magnetic transition process would lead to an additional magnetic entropy change near TC, and consequently favors the MCE. In order to compare the magnetocaloric effect in LSVMO compound with other perovskite manganites, the data of maxi occurring at the TC for mum magnetic entropy change DSmax M other relevant manganites were summarized in Table 1. We noted 1:56 J=kg K for the that for the LSVMO compound the DSmax M applied magnetic field of 1 T, which 48% of the pure Gd is about values of many other [19] is relatively larger than the DSmax M perovskite materials (Table 1). The effects of V substitution on the MCE properties have been obtained from the magnetic entropy
Acknowledgments This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0002448). This Research was also financially supported by the MKE (The Ministry of Knowledge Economy), Korea, under the ITRC (Information Technology Research Center) support program supervised by the NIPA (National IT Industry Promotion Agency) (NIPA-2012-H0301-12-2009). References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19]
D. Cui, K. Gao, P. Lu, H. Yang, Y. Liu, D. Xue, Funct. Mater. Lett. 4 (2011) 57. S. Kallel, N. Kallel, O. Pena, M. Oumezzine, Mater. Lett. 64 (2010) 1045. J. Liu, D. Xue, Nanoscale Res. Lett. 5 (2010) 1525. J. Wu, D. Xue, Nanoscale Res. Lett. 6 (2011) 14. J. Liu, D. Xue, K. Li, Nanoscale Res. Lett. 6 (2011) 138. X. Zhao, X. Ren, C. Sun, J. Xu, D. Xue, et al. Funct. Mater. Lett. 1 (2008) 167. C. Yan, D. Xue, Funct. Mater. Lett. 1 (2008) 37. K. Li, Z. Ding, D. Xue, Funct. Mater. Lett. 3 (2010) 241. M.S. Anwar, S. Kumar, N. Arshi, F. Ahmed, G.W. Kim, C.G. Lee, B.H. Koo, J. Magn. 16 (2011) 457. C. Yan, J. Liu, F. Liu, J. Wu, K. Gao, D. Xue, Nanoscale Res. Lett. 3 (2008) 473. W. Tang, W.-J. Lu, X. Luo, Y.-P. Sun, et al. Physica B 405 (2010) 2733. S. Zemni, M. Baazaoui, J. Dhahri, H. Vincent, M. Oumezzine, Mater. Lett. 63 (2009) 489. Z.B. Guo, Y.W. Du, D. Feng, et al. Phys. Rev. Lett. 78 (1997) 1142. N. Kallel, S. Kallel, A. Hagaza, M. Oumezzine, Physica B 404 (2009) 285. B.D. Cullity, C.D. Graham, Introduction to Magnetic Materials, IEEE Press, ISBN 978-0-471-47741-9, 2009. S.K. Banerjee, Phys. Lett. 12 (1964) 16. P.G. Radaelli, D.E. Cox, A.P. Ramire, et al. Phys. Rev. Lett. 75 (1995) 4488. J.B. Goodenough, Phys. Rev. B 100 (1955) 564. D.T. Morelli, A.M. Mance, J.V. Mantese, A.L. Micheli, J. Appl. Phys. 79 (1996) 373.
Contents lists available at SciVerse ScienceDirect
Materials Research Bulletin journal homepage: www.elsevier.com/locate/matresbu
Structural, magnetic and magnetocaloric properties of La0.65Sr0.35V0.1Mn0.9O3 perovskite M.S. Anwar, Shalendra Kumar, Faheem Ahmed, Nishat Arshi, Bon Heun Koo * School of Nano and Advanced Materials Engineering, Changwon National University, Changwon, Gyeongnam 641-773, South Korea
A R T I C L E I N F O
A B S T R A C T
Article history: Available online 26 April 2012
A new complex magnetic material La0.65Sr0.35V0.1Mn0.9O3, suitable for the magnetic refrigeration, has been investigated. X-ray diffraction result showed that this compound had rhombohedral structure. The substitution of manganese with V leads to a decrease in the Curie temperature, TC from 378 K to 353 K. Using Arrott plots; it was found that the phase transition for this compound is of the second-order. The magnetocaloric study exposed a quite large value of the magnetic entropy change 1.56 J/kg K and the relative cooling power value of 67 J/kg at magnetic field variation of 1 T. ß 2012 Elsevier Ltd. All rights reserved.
Keywords: A. Inorganic compounds C. X-ray diffraction D. Magnetic properties
1. Introduction Exploration of properties of inorganic material has been a longstanding goal in the development of functional materials [1–3]. There exists a close relationship among structure, morphology and property [4–7]. Extensive studies have been devoted to understanding formation mechanism from both theoretical and experimental views in order to synthesize better functional materials [8– 11]. In last decade, magnetic refrigeration is becoming promising technology to replace the conventional gas compression–expansion technique. So, increasing attention has been paid to find magnetic refrigerant that can operate near room temperature [12]. The MCE manifests as the isothermal magnetic entropy change or the adiabatic temperature change of a magnetic material when exposed to a varying magnetic field. In general, two prerequisites are necessary for inducing large MCE. One is associated with a large enough spontaneous magnetization, while the other is associated with an abrupt drop of magnetization at TC [13]. Therefore, samples exhibiting the second order magnetic phase transition are expected to show a reduced magnetic entropy change and the peak expands with the enhancement of disorder. Compared with first-order materials, second-order ones can have comparable or even larger relative cooling power (RCP), although they sometimes exhibit relatively low values of magnetic entropy change, DSM. Moreover, the absence of magnetic and thermal hysteresis are also promising features of the materials of this kind. It is therefore of significance to search for efficient magnetic refrigerants with the second-order characters.
* Corresponding author. Tel.: +82 55 264 5431; fax: +82 55 262 6486. E-mail addresses: [email protected], shafi[email protected] (B.H. Koo). 0025-5408/$ – see front matter ß 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.materresbull.2012.04.135
In this work, we present the structural and magnetocaloric properties of La0.65Sr0.35V0.1Mn0.9O3 compound. This compound belongs to the family of La1xSrxMnO3, perovskites, for which we observed a quite large value of the magnetic entropy change with the RCP value of 67 J/kg at magnetic field variation of 1 T.
2. Experimental details Ceramic samples with the nominal composition of La0.65Sr0.35MnO3 and La0.65Sr0.35V0.1Mn0.9O3 were synthesized by conventional solid-state ceramics route. The phase purity and structure of the sample were analyzed using an X-ray diffractometer (Rigaku Mini-Flex II). Magnetization measurements were performed using a quantum design vibrating sample magnetometer PPMS-6000 VSM. The magnetocaloric effect in terms of isothermal magnetic entropy change was calculated by using following equation [14]: DSM ðT; MÞ ¼
X M i M iþ2 DH i T iþ2 T i
(1)
where Mi and Mi+1 are the experimental values of the magnetization at Ti and Ti+1, respectively under a magnetic field Hi. The relative cooling power (RCP) have been calculated using the relation [14] @T SWHM RCP ðSÞ ¼ DSmax M
(2)
is the maximum magnetic entropy change and where DSmax M @TFWHM is the full width at half maximum of the magnetic entropy change curve.
M.S. Anwar et al. / Materials Research Bulletin 47 (2012) 2977–2979
2978
Fig. 1. X-ray diffraction pattern La0.65Sr0.35V0.1Mn0.9O3 compounds.
of
(a)
La0.65Sr0.35MnO3
and
(b)
3. Results and discussion Fig. 3. H/M versus M2 isotherms for La0.65Sr0.35V0.1Mn0.9O3 compound. Inset shows the isothermal magnetization curves (M–H) measured at different temperatures around TC.
The X-ray diffraction pattern of the La0.65Sr0.35V0.1Mn0.9O3 (LSVMO) compound is shown in Fig. 1. The XRD pattern indicates that LSVMO compound exhibits the polycrystalline behavior with the maximum intensity for the (1 0 4) reflection. All the reflections indexed to rhombohedral structure with R3c space group using POWDER-X software with the lattice parameters a = b = 5.5142 A˚ and c = 13.2779 A˚. No impurity peaks are observed in the pattern indicating the single phase formation of LSVMO compound. For comparison, standard XRD pattern of La0.65Sr0.35MnO3 (LSMO) is also plotted. Magnetization measurements as a function of temperature showed that our synthesized LSVMO compound exhibit a sharp ferromagnetic to paramagnetic (FM–PM) transition with increasing temperature (Fig. 2). The Curie temperature, TC is determined by two different methods: (a) determination of minimum of the derivative dM/dT of the M–T curve (not shown here), (b) by linear fitting of the Curie Weiss Law [15] in the paramagnetic region as shown in the inset of Fig. 2. The as obtained values of TC are 353 K and 378 K for LSVMO and LSMO compound, respectively. The lowering of TC for LSVMO compound is attributed to the disorder in the compound created by V doping. Since, V can be in any of its three valence states (V3+, V4+, V5+) in the LSVMO compound. But, in the view of charge neutrality and ionic radius (V4+ has a very similar ionic radius compared to that of Mn3+ and Mn4+), V4+ is expected to shift the average valence state of Mn toward to Mn3+,
which also causes a deformation in the Mn3+–O–Mn4+ network and a decrease in TC. The isothermal magnetization for LSVMO compound obtained at different temperatures is shown in Fig. 3 (inset). Below TC, magnetization increases sharply with the applied magnetic field for H < 5000 Oe. The saturation magnetization shifts to higher value of magnetic field with the decreasing temperature, which confirms the FM behavior of our sample at low temperature. In order to get a deeper insight of the type of magnetic phase transition, we derive the Arrott plots (H/M vs. M2) from M–H plots and the results are shown in Fig. 3. The second order magnetic phase transition behavior occurs because of the positive slope in the high magnetic field regions for the LSVMO compound [16]. The evolution of magnetization obtained at different temperatures for LSVMO compound reveals a strong variation of magnetization around the TC (Fig. 3). It indicates that there is a possible large magnetic entropy change associated with the FM– PM transition temperature, occurring at TC. In order to investigate this idea, we have calculated the magnetic entropy change using Eq. (1). The magnetic entropy change data as a function of temperature at various applied magnetic fields for the LSVMO compound are plotted in Fig. 4. The maximum of the magnetic
Fig. 2. Temperature dependence of magnetization for (a) La0.65Sr0.35MnO3 and (b) La0.65Sr0.35V0.1Mn0.9O3 compounds at a magnetic field of 0.5 T. The inset is the plot of Curie Weiss Law vs. temperature.
Fig. 4. Magnetic entropy change of La0.65Sr0.35V0.1Mn0.9O3 compound at different versus applied magnetic fields as a function of temperature. The inset is the DSmax M applied magnetic field.
M.S. Anwar et al. / Materials Research Bulletin 47 (2012) 2977–2979 Table 1 Comparison of reported values of the maximum magnetic entropy change occurring at the Curie temperature and a magnetic field change (DH), for various perovskite manganites and gadolinium metal. Composition
TC (K)
DT (T)
DSmax (J/kg K)
RCP (J/kg)
References
Gd La0.7Sr0.3Mn0.8Cr0.2O3 La0.67Sr0.33MnO3 La0.75Sr0.25MnO3 La0.65Sr0.35MnO3 La0.65Sr0.35V0.1Mn0.9O3
293 286 348 340 378 353
1 2 5 1.5 1 1
3.25 1.20 1.69 1.5 0.99 1.56
– 59 211 65 40 67
[17] [18] [14] [19] Our work Our work
2979
change of La0.65Sr 0.35MnO3 compound (inset of Fig. 5). Around reaches a maximum value of about 0.99 J/kg K 376 K, the DSmax M upon the magnetic field variation of 1 T. The most important factor for selecting magnetic refrigerants is based on the cooling power per unit volume, namely, the relative cooling power (RCP). The material with a larger RCP value usually represents a better magnetocaloric substance due to its high cooling efficiency. RCP values for the LSVMO compound exhibits a linear rise with increasing field, as shown in Fig. 5. From Fig. 5 we also conclude and RCP for the LSVMO compound are that the values of DSmax M greater than those of LSMO. As a result, the La0.65Sr0.35V0.1Mn0.9O3 (LSVMO) compound can be used as potential magnetic refrigerant. 4. Conclusions Synthesis, structural and magnetic characterization of La0.65Sr0.35V0.1Mn0.9O3 compound were performed. X-ray analyses reveal that this material crystallizes in a rhombohedral structure with R3c space group. The V doping leads to the change in Mn–O bond length and Mn–O–Mn bond angle, consequently, the Curie temperature decreased. The obtained compound exhibits a large MCE, which can be attributed to an abrupt magnetization change due to the phase transition near TC. The Arrott plots reveal that the phase transition for this compound is of the second-order and the maximum change in magnetic entropy reaches 1.56 J/kg K in a magnetic field variation of 1 T. The RCP is relatively large; it is about 67 J/kg at magnetic field of 1 T. These results indicate that La0.65Sr0.35V0.1Mn0.9O3 compound is a good candidate as potential magnetic refrigerant with sufficient performance.
Fig. 5. Relative cooling power values versus applied magnetic field for La0.65Sr0.35V0.1Mn0.9O3 compound, inset shows the comparison of magnetic entropy change of La0.65Sr0.35MnO3 and La0.65Sr0.35V0.1Mn0.9O3 compounds.
entropy changes is obtained around 350 K. This temperature is near the Curie temperature of the sample (TC = 353 K). We can see from Fig. 4 that the magnetic entropy change depends on the applied magnetic field change. The larger the magnetic field is, the bigger the magnetic entropy change shall be. The maximum of the upon the applied magnetic field magnetic entropy change DSmax M changes (DH) of 1 and 4 T are about 1.56 and 4.33 J/kg K, exhibits a linear rise with increasing field respectively. DSmax M as shown in the inset of Fig. 4, which indicates much larger entropy change to be expected at higher magnetic field, signifying the effect of spin–lattice coupling associated to changes in the magnetic ordering process in the LSVMO compound [12]. With the observation of large magnetic entropy change and the fact that a strong spin–lattice coupling exists in perovskite manganites, a conclusion can be drawn that a strong spin–lattice coupling in the magnetic transition process would lead to an additional magnetic entropy change near TC, and consequently favors the MCE. In order to compare the magnetocaloric effect in LSVMO compound with other perovskite manganites, the data of maxi occurring at the TC for mum magnetic entropy change DSmax M other relevant manganites were summarized in Table 1. We noted 1:56 J=kg K for the that for the LSVMO compound the DSmax M applied magnetic field of 1 T, which 48% of the pure Gd is about values of many other [19] is relatively larger than the DSmax M perovskite materials (Table 1). The effects of V substitution on the MCE properties have been obtained from the magnetic entropy
Acknowledgments This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0002448). This Research was also financially supported by the MKE (The Ministry of Knowledge Economy), Korea, under the ITRC (Information Technology Research Center) support program supervised by the NIPA (National IT Industry Promotion Agency) (NIPA-2012-H0301-12-2009). References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19]
D. Cui, K. Gao, P. Lu, H. Yang, Y. Liu, D. Xue, Funct. Mater. Lett. 4 (2011) 57. S. Kallel, N. Kallel, O. Pena, M. Oumezzine, Mater. Lett. 64 (2010) 1045. J. Liu, D. Xue, Nanoscale Res. Lett. 5 (2010) 1525. J. Wu, D. Xue, Nanoscale Res. Lett. 6 (2011) 14. J. Liu, D. Xue, K. Li, Nanoscale Res. Lett. 6 (2011) 138. X. Zhao, X. Ren, C. Sun, J. Xu, D. Xue, et al. Funct. Mater. Lett. 1 (2008) 167. C. Yan, D. Xue, Funct. Mater. Lett. 1 (2008) 37. K. Li, Z. Ding, D. Xue, Funct. Mater. Lett. 3 (2010) 241. M.S. Anwar, S. Kumar, N. Arshi, F. Ahmed, G.W. Kim, C.G. Lee, B.H. Koo, J. Magn. 16 (2011) 457. C. Yan, J. Liu, F. Liu, J. Wu, K. Gao, D. Xue, Nanoscale Res. Lett. 3 (2008) 473. W. Tang, W.-J. Lu, X. Luo, Y.-P. Sun, et al. Physica B 405 (2010) 2733. S. Zemni, M. Baazaoui, J. Dhahri, H. Vincent, M. Oumezzine, Mater. Lett. 63 (2009) 489. Z.B. Guo, Y.W. Du, D. Feng, et al. Phys. Rev. Lett. 78 (1997) 1142. N. Kallel, S. Kallel, A. Hagaza, M. Oumezzine, Physica B 404 (2009) 285. B.D. Cullity, C.D. Graham, Introduction to Magnetic Materials, IEEE Press, ISBN 978-0-471-47741-9, 2009. S.K. Banerjee, Phys. Lett. 12 (1964) 16. P.G. Radaelli, D.E. Cox, A.P. Ramire, et al. Phys. Rev. Lett. 75 (1995) 4488. J.B. Goodenough, Phys. Rev. B 100 (1955) 564. D.T. Morelli, A.M. Mance, J.V. Mantese, A.L. Micheli, J. Appl. Phys. 79 (1996) 373.