Theoretical Investigation On The Existence Of Inverse And Direct Magnetocaloric Effect In Perovskite Euzro 3

We report on the magnetic and magnetocaloric effect calculations in antiferromagnetic perovskite-type EuZrO 3. The theoretical investigation was carried out using a model Hamiltonian including the exchange interactions between nearest-neighbor and next-nearest-neighbor for the antiferromagnetic ideal G-type structure (the tolerance factor for EuZrO 3 is t = 0.983, which characterizes a small deformation from an ideal cubic perovskite). The molecular field approximation and Monte Carlo simulation were considered and compared. The calculated magnetic susceptibility is in good agreement with the available experimental data. For a magnetic field change from zero to 2 T a normal magnetocaloric effect was calculated and for a magnetic field change from zero to 1 T, an inverse magnetocaloric effect was predicted to occur below T = 3.6 K. © 2011 American Institute of Physics.1098Warburg, E., (1881) Ann. Phys., 13, p. 141. , 10.1002/andv249:5Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 10.1103/PhysRevLett.78.4494Von Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) J. Magn. Magn. Mater., 277, p. 78. , 10.1016/j.jmmm.2003.10.013De Oliveira, N.A., Von Ranke, P.J., (2008) Phys. Rev. B, 77, p. 214439. , 10.1103/PhysRevB.77.214439Von Ranke, P.J., De Oliveira, N.A., Plaza, E.J.R., De Sousa, V.S.R., Alho, B.P., Magnus, A., Carvalho, G., Reis, M.S., (2008) J. Appl. Phys., 104, p. 093906. , 10.1063/1.3009974Sande, P., Hueso, L.E., Miguens, D.R., Rivas, J., Rivadulla, F., Lopez-Quintela, M.A., (2001) Appl. Phys. Lett., 79, p. 2040. , 10.1063/1.1403317Yamada, H., Goto, T., (2004) Physica B, 346-347, p. 104. , 10.1016/j.physb.2004.01.029Nobrega, E.P., De Oliveira, N.A., Von Ranke, P.J., Troper, A., (2006) Phys. Rev. B, 74, p. 144429. , 10.1103/PhysRevB.74.144429Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , 1st ed. (Institute of Physics, Bristol)De Oliveira, N.A., Von Ranke, P.J., (2010) Phys. Rep., 489, p. 89. , 10.1016/j.physre2009.12.006Sasaki, S., Prewitt, C.T., Liebermann, R.C., (1983) Am. Mineral., 68, p. 1189Kuz'Min, M.D., Tishin, A.M., (1991) J. Phys. D: Appl. Phys., 24, p. 2039. , 10.1088/0022-3727/24/11/020Kimura, H., Numazawa, T., Sato, M., Ikeya, T., Fukuda, T., (1995) J. Appl. Phys., 77, p. 432. , 10.1063/1.359349Phan, M.-H., Yu, S.-C., Review of the magnetocaloric effect in manganite materials (2007) Journal of Magnetism and Magnetic Materials, 308 (2), pp. 325-340. , DOI 10.1016/j.jmmm.2006.07.025, PII S0304885306009577Zong, Y., Fujita, K., Akamatsu, H., Murai, S., Tanaka, K., (2010) J. Solid State Chem., 183, p. 168. , 10.1016/j.jssc.2009.10.014Kolodiazhnyi, T., Fujita, K., Wang, L., Zong, Y., Tanaka, K., Sakka, Y., Takayama-Muromachi, E., (2010) Appl. Phys. Lett., 96, p. 252901. , 10.1063/1.3456730Greedan, J.E., Chien, C.-L., Johnston, R.G., (1976) J. Solid State Chem., 19, p. 155. , 10.1016/0022-4596(76)90163-8Nobrega, E.P., De Oliveira, N.A., Von Ranke, P.J., Troper, A., Monte Carlo calculations of the magnetocaloric effect in Gd5(SixGe1-x)4 compounds (2005) Physical Review B - Condensed Matter and Materials Physics, 72 (13), pp. 1-7. , http://oai.aps.org/oai/?verb=ListRecords&metadataPrefix= oai_apsmeta_2&set=journal:PRB:72, DOI 10.1103/PhysRevB.72.134426, 134426Nbrega, E.P., De Oliveira, N.A., Von Ranke, P.J., Troper, A., (2008) J. Magn. Magn. Mater., 320, p. 147. , 10.1016/j.jmmm.2008.02.036Landau, D.P., Binder, K., (2000) A Guide to Monte Carlo Simulations in Statistical Physics, , (Cambridge University Press, Cambridge)Yang, H., Ohishi, Y., Kurosaki, K., Muta, H., Yamanaka, S., (2010) J. Alloys Compd., 504, p. 201. , 10.1016/j.jallcom.2010.05.088Terki, R., Bertrand, G., Aourag, H., Coddet, C., Thermal properties of Ba 1-xSr xZrO 3 compounds from microscopic theory (2008) Journal of Alloys and Compounds, 456 (1-2), pp. 508-513. , DOI 10.1016/j.jallcom.2007.02.133, PII S0925838807005397Bagayoko, D., Zhao, G.L., Fan, J.D., Wang, J.T., (1998) J. Phys. Condens. Matter, 10, p. 5645. , 10.1088/0953-8984/10/25/014Von Ranke, P.J., Mota, M.A., Grangeia, D.F., Carvalho, A.M.G., Gandra, F.C.G., Coelho, A.A., Caldas, A., Gama, S., Magnetocaloric effect in the RNi 5 (R = Pr, Nd, Gd, Tb, Dy, Ho, Er) series (2004) Physical Review B - Condensed Matter and Materials Physics, 70 (13), pp. 1344281-1344286. , DOI 10.1103/PhysRevB.70.134428, 13442

The Giant Anisotropic Magnetocaloric Effect In Dyal2

We report on calculations of the anisotropic magnetocaloric effect in DyAl2 using a model Hamiltonian including crystalline electrical field effects. The anisotropic effect is produced by the rotation of a constant magnetic field from the easy to a hard magnetic direction in the crystal and is enhanced by the first order nature of the field induced spin reorientation transition. The calculated results indicate that for a field with modulus of 2 T rotating from a hard to the easy direction, the isothermal magnetic entropy (Δ Siso) and adiabatic temperature (Δ Tad) changes present peak values higher than 60% the ones observed in the usual process, in which the field direction is kept constant and the modulus of the field is varied. © 2008 American Institute of Physics.1049Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , 1st ed. (Institute of Physics, Bristol)Warburg, E., (1881) Ann. Phys. (N.Y.), 13, p. 141. , 0003-4916Brown, G.V., (1976) J. Appl. Phys., 47, p. 3673. , 0021-8979 10.1063/1.323176Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 0031-9007 10.1103/PhysRevLett.78.4494Von Ranke, P.J., De Oliveira, N.A., Mello, C., Garcia, D.C., De Souza, V.A., Magnus, A., Carvalho, G., (2006) Phys. Rev. B, 74, p. 054425. , 0163-1829 10.1103/PhysRevB.74.054425Hill, T.W., Wallace, W.E., Craig, R.S., Inuone, T.J., (1973) Solid State Chem., 8, p. 364. , 10.1016/S0022-4596(73)80036-2De Oliveira, I.G., Garcia, D.C., Von Ranke, P.J., (2007) J. Appl. Phys., 102, p. 073907. , 0021-8979 10.1063/1.2783781Lima, A.L., Tsokol, A.O., Gschneidner Jr., K.A., Pecharky, V.K., Lograsso, T.A., Schlagel, D.L., (2005) Phys. Rev. B, 72, p. 024403. , 0163-1829 10.1103/PhysRevB.72.024403Von Ranke, P.J., De Oliveira, I.G., Guimarães, A.P., Da Silva, X.A., (2000) Phys. Rev. B, 61, p. 447. , 0163-1829 10.1103/PhysRevB.61.447Von Ranke, P.J., De Oliveira, N.A., Garcia, D.C., De Sousa, V.S.R., De Souza, V.A., Magnus, A., Carvalho, G., Reis, M.S., (2007) Phys. Rev. B, 75, p. 184420. , 0163-1829 10.1103/PhysRevB.75.184420Purwins, H.G., Leson, A., (1990) Adv. Phys., 39, p. 309. , 0001-8732 10.1080/00018739000101511Von Ranke, P.J., Pecharsky, V.K., Gschneidner Jr., K.A., (1998) Phys. Rev. B, 58, p. 1211

A Comparative Study Of The Magnetocaloric Effect In Rni2 (r=nd,gd,tb) Intermetallic Compounds

Conventional and anisotropic magnetocaloric effects were studied in cubic rare earth RNi2 (R=Nd,Gd,Tb) ferromagnetic intermetallic compounds. These three compounds are representative of small, null, and large magnetocrystalline anisotropy in the series, respectively. Magnetic measurements were performed in polycrystalline samples in order to obtain the isothermal magnetocaloric data, which were confronted with theoretical results based on mean field calculations. For the R=Tb case, we explore the crystalline electrical-field anisotropy to predict the anisotropic magnetocaloric behavior due to the rotation of an applied magnetic field of constant intensity. Our results suggest the possibility of using both conventional and anisotropic magnetic entropy changes to extend the range of temperatures for use in the magnetocaloric effect. © 2009 American Institute of Physics.1051Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 0031-9007 10.1103/PhysRevLett.78.4494Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Appl. Phys. Lett., 70, p. 3299. , 0003-6951 10.1063/1.119206Von Ranke, P.J., De Oliveira, N.A., Mello, C., Garcia, D.C., De Souza, V.A., Carvalho, A.M.G., (2006) Phys. Rev. B, 74, p. 054425. , 0163-1829 10.1103/PhysRevB.74.054425De Oliveira, I.G., Garcia, D.C., Von Ranke, P.J., (2007) J. Appl. Phys., 102, p. 073907. , 0021-8979 10.1063/1.2783781Lima, A.L., Tsokol, A.O., Gschneidner Jr., K.A., Pecharsky, V.K., Lograsso, T.A., Schlagel, D.L., (2005) Phys. Rev. B, 72, p. 024403. , 0163-1829 10.1103/PhysRevB.72.024403Von Ranke, P.J., De Oliveira, N.A., Garcia, D.C., De Souza, V.S.R., De Souza, V.A., Carvalho, A.M.G., Gama, S., Reis, M.S., (2007) Phys. Rev. B, 75, p. 184420. , 0163-1829 10.1103/PhysRevB.75.184420Carvalho, A.M.G., Campoy, J.C.P., Coelho, A.A., Plaza, E.J.R., Gama, S., Von Ranke, P.J., (2005) J. Appl. Phys., 97, p. 083905. , 0021-8979 10.1063/1.1876575Plaza, E.J.R., De Sousa, V.S.R., Alho, B.P., Von Ranke, P.J., (unpublished)Von Ranke, P.J., De Oliveira, N.A., Plaza, E.J.R., De Souza, V.S.R., Alho, B., Carvalho, A.M.G., Gama, S., Reis, M.S., (2008) J. Appl. Phys., 104, p. 093906. , 0021-8979 10.1063/1.3009974Lindbaum, A., Gratz, E., Heathman, S., (2002) Phys. Rev. B, 65, p. 134114. , 0163-1829 10.1103/PhysRevB.65.134114Purwins, H.G., Leson, A., (1990) Adv. Phys., 39, p. 309. , 0001-8732 10.1080/00018739000101511Lea, K.R., Leask, M.J.M., Wolf, W.P., (1962) J. Phys. Chem. Solids, 23, p. 1381. , 0022-3697 10.1016/0022-3697(62)90192-0Stevens, K.W.H., (1952) Proc. Phys. Soc., London, Sect. A, 65, p. 209. , 0370-1298 10.1088/0370-1298/65/3/308Von Ranke, P.J., Pecharsky, V.K., Gschneidner Jr., K.A., (1998) Phys. Rev. B, 58, p. 12110. , 0163-1829 10.1103/PhysRevB.58.12110Von Ranke, P.J., Nóbrega, E.P., De Oliveira, I.G., Gomes, A.M., Sarthour, R.S., (2001) Phys. Rev. B, 63, p. 184406. , 0163-1829 10.1103/PhysRevB.63.18440

Magnetocaloric Effect Due To Spin Reorientation In The Crystalline Electrical Field: Theory Applied To Dy Al2

We report a way of obtaining the magnetocaloric effect due to the crystal electrical-field quenching of the total angular momentum in a magnetic system where a strong spin reorientation is present. The theoretical model is applied to Dy Al2 and the results predict a considerable magnetic entropy change by rotating a single crystal in a fixed magnetic field. The obtained temperature and magnetic-field dependencies of the magnetization component along the 111-crystallographic direction are in good agreement with the recently reported experimental data. © 2007 The American Physical Society.7518Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , PRLTAO 0031-9007 10.1103/PhysRevLett.78.4494Choe, W., Pecharsky, V.K., Pecharsky, A.O., Gschneidner Jr., K.A., Young Jr., V.G., Miller, G.J., (2000) Phys. Rev. Lett., 84, p. 4617. , PRLTAO 0031-9007 10.1103/PhysRevLett.84.4617Provenzano, V., Shapiro, A.J., Shull, R.D., (2004) Nature (London), 429, p. 853. , NATUAS 0028-0836 10.1038/nature02657Tegus, O., Brück, E., Buschow, K.H.J., De Boer, F.R., (2002) Nature (London), 415, p. 150. , NATUAS 0028-0836 10.1038/415150AWada, H., Tanabe, Y., (2001) Appl. Phys. Lett., 79, p. 3302. , APPLAB 0003-6951 10.1063/1.1419048Wada, H., Morikawa, T., Taniguchi, K., Shibata, T., Yamada, Y., Akishige, Y., (2003) Physica B, 328, p. 114. , PHYBE3 0921-4526 10.1016/S0921-4526(02)01822-7Hu, F., Shen, B., Sun, J., Cheng, Z., Rao, G., Zhang, X., (2001) Appl. Phys. Lett., 78, p. 3675. , APPLAB 0003-6951 10.1063/1.1375836Fujita, A., Fujieda, S., Hasegawa, Y., Fukamichi, K., (2003) Phys. Rev. B, 67, p. 104416. , PRBMDO 0163-1829 10.1103/PhysRevB.67.104416Von Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) J. Magn. Magn. Mater., 277, p. 78. , JMMMDC 0304-8853 10.1016/j.jmmm.2003.10.013Von Ranke, P.J., De Campos, N.A., Caron, L., Coelho, A.A., Gama, S., De Oliveira, N.A., (2004) Phys. Rev. B, 70, p. 094410. , PRBMDO 0163-1829 10.1103/PhysRevB.70.094410Von Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) Phys. Lett. a, 320, p. 302. , PYLAAG 0375-9601 10.1016/j.physleta.2003.10.067Gama, S., Coelho, A.A., De Campos, A., Carvalho, A.M., Gandra, F.C.G., Von Ranke, P.J., De Oliveira, N.A., (2004) Phys. Rev. Lett., 93, p. 237202. , PRLTAO 0031-9007 10.1103/PhysRevLett.93.237202Von Ranke, P.J., De Oliveira, N.A., Mello, C., Carvalho, A.M., Gama, S., (2005) Phys. Rev. B, 71, p. 054410. , PRBMDO 0163-1829 10.1103/PhysRevB.71.054410Von Ranke, P.J., Gama, S., Coelho, A.A., De Campos, A., Carvalho, A.M., Gandra, F.C.G., De Oliveira, N.A., (2006) Phys. Rev. B, 73, p. 014415. , PRBMDO 0163-1829 10.1103/PhysRevB.73.014415Von Ranke, P.J., Pecharsky, V.K., Gschneidner, K.A., Korte, B.J., (1998) Phys. Rev. B, 58, p. 14436. , PRBMDO 0163-1829 10.1103/PhysRevB.58.14436Von Ranke, P.J., Mota, M.A., Grangeia, D.F., Carvalho, A.M., Gandra, F.C.G., Coelho, A.A., Caldas, A., Gama, S., (2004) Phys. Rev. B, 70, p. 134428. , PRBMDO 0163-1829 10.1103/PhysRevB.70.134428Lima, A.L., Oliveira, I.S., Gomes, A.M., Von Ranke, P.J., (2002) Phys. Rev. B, 65, p. 172411. , PRBMDO 0163-1829 10.1103/PhysRevB.65.172411Von Ranke, P.J., Lima, A.L., Nobrega, E.P., Da Silva, X.A., Guimarães, A.P., Oliveira, I.S., (2000) Phys. Rev. B, 63, p. 024422. , PRBMDO 0163-1829 10.1103/PhysRevB.63.024422Lima, A.L., Tsokol, A.O., Gschneidner Jr., K.A., Pecharky, V.K., Lograsso, T.A., Schlagel, D.L., (2005) Phys. Rev. B, 72, p. 024403. , PRBMDO 0163-1829 10.1103/PhysRevB.72.024403Von Ranke, P.J., De Oliveira, I.G., Guimarães, A.P., Da Silva, X.A., (2000) Phys. Rev. B, 61, p. 447. , PRBMDO 0163-1829 10.1103/PhysRevB.61.447Bak, P., (1974) J. Phys. C, 7, p. 4097. , JPSOAW 0022-3719 10.1088/0022-3719/7/22/014Hutchings., M.T., (1964) Solid State Phys., 16, p. 227. , SSPHAE 0081-1947Lea, K.R., Leask, M.J.M., Wolf, W.P., (1962) J. Phys. Chem. Solids, 33, p. 1381. , JPCSAW 0022-3697Stevens, K.W.H., (1952) Proc. Phys. Soc., London, Sect. a, 65, p. 209. , PPSAAM 0370-1298 10.1088/0370-1298/65/3/308Purwins, H.G., Leson, A., (1990) Adv. Phys., 39, p. 309. , ADPHAH 0001-8732 10.1080/00018739000101511Kuz'Min, M.D., Tishin, A.M., (1991) J. Phys. D, 24, p. 2039. , JPAPBE 0022-3727 10.1088/0022-3727/24/11/02

The Influence Of Spontaneous And Field-induced Spin Reorientation Transitions On The Magnetocaloric Properties Of Hozn And Erzn

We report a theoretical investigation on the magnetocaloric properties of the cubic CsCl-type HoZn and ErZn compounds. Several anomalies in the magnetocaloric quantities, ΔS T and ΔT S, are observed due to spontaneous and/or field-induced spin reorientation transitions in these compounds. In HoZn, a discontinuity in the isothermal entropy change and in the adiabatic temperature change around T 1 23 K is ascribed to the spontaneous reorientation transition. Under a magnetic field variation from 0 up to 2 T in the 110 and 100 directions, an almost table-like behavior in S T is predicted between T 1 and T SR1. The peak around the ferromagnetic-paramagnetic transition temperature in the magnetocaloric quantities shows a dependence on the direction of the applied field. For μ 0ΔH = 2 T, it reaches 11.9 J/kgK (magnetic field along the 111 direction) and 7.9 J/kg K (magnetic field in the 100 direction). In ErZn there is also a dependence of ΔS T and ΔT S on field direction. From the analysis of the spin reorientations in both compounds we have built spin reorientation diagrams that summarize their temperature and field dependence. Our theoretical approach is based on a model Hamiltonian that includes exchange, crystal field, and quadrupolar interactions. © 2011 American Institute of Physics.1096Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 10.1103/PhysRevLett.78.4494Morellon, L., Magen, C., Algarabel, P.A., Ibarra, M.R., Ritter, C., (2001) Appl. Phys. Lett., 79, p. 1318. , 10.1063/1.1399007Wada, H., Tanabe, Y., (2001) Appl. Phys. Lett., 79, p. 3302. , 10.1063/1.1419048Hu, F.X., Shen, B.G., Sun, J.R., Cheng, Z.H., Rao, G.H., Zhang, X.X., (2001) Appl. Phys. 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Physique., 40, p. 141Singh, N.K., Kumar, P., Suresh, K.G., Coelho, A.A., Gama, S., Nigam, A.K., Effect of Tm substitution on the magnetic and magnetocaloric properties in the intermetallic compounds (Tb 1-xTm x)Co 2 (2007) Journal of Physics D: Applied Physics, 40 (6), pp. 1620-1625. , DOI 10.1088/0022-3727/40/6/005, PII S0022372707369295, 005Tohei, T., Wada, H., (2004) J. Magn. Magn. Mater., 280, p. 101. , 10.1016/j.jmmm.2004.02.026Singh, N.K., Kumar, P., Suresh, K.G., Nigam, A.K., Coelho, A.A., Gama, S., Measurement of pressure effects on the magnetic and the magnetocaloric properties of the intermetallic compounds DyCo 2 and Er(Co 1-xSi x) 2 (2007) Journal of Physics Condensed Matter, 19 (3), p. 036213. , DOI 10.1088/0953-8984/19/3/036213, PII S0953898407358074Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , (IOP, Bristol

Theoretical Investigation On The Anisotropic Magnetocaloric Effect: Application To Dyal2

Using a simple model Hamiltonian, the formulation of the anisotropic MCE was introduced and the calculations performed for DyAl2 leads to quantitative values of ΔSiso[0 0 1][1 0 0]. An anomalous MCE was also predicted when the magnetic field is applied along the non-easy magnetization direction [0 0 1]. © 2008.32014e143e146Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications. first ed., , Institute of Physics, Bristol and PhiladelphiaPecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494von Ranke, P.J., de Oliveira, N.A., Mello, C., Carvalho, A.M.G., Gama, S., (2005) Phys. Rev. B, 71, p. 054410de Campos, A., Rocco, D.L., Carvalho, A.M.G., Caron, L., Coelho, A.A., Gama, S., da Silva, L.M., de Oliveira, N.A., (2006) Nat. Mater., 5, p. 802Lea, K.R., Leask, M.J.M., Wolf, W.P., (1962) J. Phys. Chem. Solids, 33, p. 1381Purwins, H.G., Leson, A., (1990) Adv. Phys., 39, p. 309Lima, A.L., Tsokol, A.O., Gschneidner Jr., K.A., Pecharky, V.K., Lograsso, T.A., Schlagel, D.L., (2005) Phys. Rev. B, 72, p. 024403von Ranke, P.J., Pecharsky, V.K., Gschneidner Jr., K.A., (1998) Phys. Rev. B, 58, p. 1211

The Influence Of Magnetic And Electric Coupling Properties On The Magnetocaloric Effect In Quantum Paraelectric Eutio 3

We report on the magnetic and magnetocaloric effect calculations in antiferromagnetic perovskite-type EuTiO 3. From the isothermal magnetic entropy change calculated upon low magnetic field changes (below 1 T) several results were predicted: inverse magnetocaloric effect, latent heat associated to spin AFM-FM reorientation transition and a temperature interval (controlled by magnetic field) where the EuTiO 3 does not change heat in an isothermic process. The magnetocaloric effect described through magnetic entropy change was correlated with magnetocapacitance formula. The theoretical investigation was carried out using a Heisenberg Hamiltonian considering the G-type antiferromagnetic structure with exchange interactions, in mean field approximation, between nearest-neighbor and next-nearest-neighbor magnetic Eu 2 ions. © 2011 Elsevier B.V. All rights reserved.324712901295Warburg, E., (1881) Annals of Physics, 13, p. 141Debye, Ann.P., (1926) Physik, 81, p. 1154Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Physical Review Letters, 78, p. 4494De Oliveira, N.A., Von Ranke, P.J., (2010) Physics Report, 489, p. 89De Souza, V.S.R., Magnus, A., Carvalho, G., Plaza, E.J.R., Alho, B.P., Tedesco, J.C.G., Coelho, A.A., Von Ranke, P.J., (2011) Journal of Magnetism and Magnetic Materials, 323, p. 794Alho, B.P., De Oliveira, N.A., De Sousa, V.S.R., Plaza, E.J.R., Magnus, A., Carvalho, G., Von Ranke, P.J., (2010) Journal of Physics Condensed Matter, 22, p. 486008Sande, P., Hueso, L.E., Miguens, D.R., Rivas, J., Rivadulla, F., Lopez-Quintela, M.A., (2001) Applied Physics Letters, 79, p. 2040Nobrega, E.P., De Oliveira, N.A., Von Ranke, P.J., Troper, A., (2006) Physical Review B, 74, p. 144429Yamada, H., Goto, T., (2004) Physica B, 346, p. 104Spaldin, N.A., Fiebig, M., (2005) Science, 309, p. 391Fiebig, M., (2005) Journal of Physics D: Applied Physics, 38, pp. R123-R152Katsufuji, T., Takagi, H., (2001) Physical Review B, 64, p. 054415Kolodiazhnyi, T., Fujita, F., Wang, L., Zong, Y., Tanaka, K., Sakka, Y., Takayama-Muromachi, E., (2010) Applied Physics Letters, 96, p. 252901Qing, J., Hua, W., (2002) Chinese Physics, 11, p. 1303Lines, M.E., Glass, A.M., (1977) Principles and Applications of Ferroelectrics and Related Materials, , Oxford ClarendonFennie, C.J., Rabe, K.M., (2006) Physical Review Letters, 96, p. 205505Sushkov, A.B., Tchernyshyov, O., Ratcliff, I.I.W., Cheong, S.W., Drew, H.D., (2005) Physical Review Letters, 94, p. 137202Fennie, C.J., Rabe, K.M., (2006) Physical Review Letters, 97, p. 267602McGuire, T.R., Shafer, M.W., Joenk, R.J., Alperin, H.A., Pickart, S.J., (1966) Journal of Applied Physics, 37, p. 98

Theoretical Investigation On The Magnetocaloric Effect In Mnas Using A Microscopic Model To Describe The Magnetic And Thermal Hysteresis

We report the thermal and magnetic hysteresis diagram for MnAs that comes from a microscopic description of a magnetic system through a model Hamiltonian that takes into account the magnetoelastic interaction. The temperature and magnetic hysteresis intervals are governed by the magnetoelastic interaction parameter, which leads to the energy barrier between stable and metastable minima in the exact free energy, obtained from our microscopic model. Application of the model to the MnAs first-order magnetic material, which presents high hysteresis effect, leads to a good agreement with the experimental magnetic and magnetocaloric data. © 2012 Elsevier Ltd. All rights reserved.15211951954Pecharsky, V.K., Gschneidner, Jr.K.A., (1997) Phys. Rev. Lett., 78, p. 4494Pecharsky, V.K., Gschneidner, Jr.K.A., (1998) Adv. Cryog. Eng., 43, p. 1729Gschneidner, Jr.K.A., Pecharsky, V.K., (2000) Mater. Sci. Eng. A, 287, p. 301Pecharsky, V.K., Gschneidner, Jr.K.A., (2001) Adv. Mater., 13, p. 683Hu, F., Shen, B., Sun, J., Cheng, Z., (2001) Appl. Phys. Lett., 78, p. 3675Wada, H., Tanabe, Y., (2001) Appl. Phys. Lett., 79, p. 3302Wada, H., Taniguchi, K., Tanabe, Y., (2002) Mater. Trans., JIM, 43, p. 73Wada, H., Morikawa, T., Taniguchi, K., Shibata, T., Yamada, Y., Akishige, Y., (2002) Physica B, 328, p. 114Tegus, O., Brück, E., Buschow, K.H.J., De Boer, F.R., (2002) Nature, 415, p. 150Tegus, O., Brück, E., Zhang, L., Dagula, W., Buschow, K.H.J., De Boer, F.R., (2002) Physica B, 319, p. 174Fujita, A., Fujieda, S., Hasegawa, Y., Fukamich, K., (2003) Phys. Rev. B, 67, p. 104416Strässle, Th., Furrer, A., Hossain, Z., Geibel, Ch., (2003) Phys. Rev. B, 67, p. 054407Von Ranke, P.J., De Oliveira, N.A., Alho, B.P., De Sousa, V.S.R., Plaza, E.J.R., Carvalho, A.M.G., (2010) J. Magn. Magn. Mater., 322, pp. 84-87Strässle, Th., Juranyi, F., Schneider, M., Janssen, S., Furrer, A., Krämer, K.W., Güdel, H.U., (2004) Phys. Rev. Lett, 92, p. 257202Castellano, G., (2003) J. Magn. Magn. Mater., 260, p. 146Bean, C.P., Rodbell, D.S., (1962) Phys. Rev., 126, p. 104Von Ranke, P.J., De Campos, A., Caron, L., Coelho, A.A., Gama, S., De Oliveira, N.A., (2004) Phys. Rev. B, 70, p. 094410Neumann, K.U., Dann, S., Fröhlich, K., Murani, A., Ouladdiaf, B., Ziebeck, K.R.A., (2005) Lect. Notes Phys., 678, pp. 87-96Magnus, A., Carvalho, G., Coelho, A.A., Gama, S., Gandra, F.C.G., Von Ranke, P.J., De Oliveira, N.A., (2009) Eur. Phys. J. B, 68, pp. 67-72Huang, K., (1987) Statistical Mechanics, 17 CHAPTER, p. 428. , 2 nd ed. Wiley New JerseyVon Ranke, P.J., Gama, S., Coelho, A.A., De Campos, A., Magnus, A., Carvalho, G., Gandra, F.C.G., De Oliveira, N.A., (2006) Phys. Rev. B, 73, p. 014415Magnus, A., Carvalho, G., Coelho, A.A., Von Ranke, P.J., Alves, C.S., (2011) J. Alloys Compd, 509, p. 345

Exchange-bias-like Effect In Pr0.75tb0.25al 2 And Pr0.7tb0.3al2 Samples

The magnetic behavior of pseudobinary Pr0.7Tb 0.3Al2 and Pr0.75Tb0.25Al 2 compounds was studied, and a predominant ferrimagnetic ordering was observed. Noteworthy characteristics such as negative magnetization, compensation points and exchange-bias-like (EB-like) effect were found. This EB-like effect was observed at temperatures below the compensation points. The effect is somewhat different from the one already studied in similar systems combining light and heavy rare earths. The results indicate that the EB-like effect characteristics are related to the conduction electron magnetic polarization and an induced unidirectional anisotropy present in these compounds. © 2013 Elsevier B.V. All rights reserved.339610Williams, H.J., Wernick, J.H., Sherwood, R.C., Nesbitt, E.A., (1962) Journal of the Physical Society of Japan, 17, p. 91Swift, W.M., Wallace, W.E., (1968) Journal of Physics and Chemistry of Solids, 29, p. 2053Oesterreicher, H., (1974) Inorganic Chemistry, 13, p. 2807Bouziane, K., Carboni, C., Morrison, C., (2008) Journal of Physics: Condensed Matter, 20, p. 025218Levin, E.M., Pecharsky, V.K., Gschneidner, K.A., (2001) Journal of Applied Physics, 90, p. 6255Inoue, T., Sankar, S.G., Craig, R.S., Wallace, W.E., Gschneidner, K.A., (1977) Journal of Physics and Chemistry of Solids, 38, p. 487Holden, T.M., Buyers, W.J.L., Purwins, H.G., (1984) Journal of Physics F: Metal Physics, 14, p. 2701Carvalho, A.M.G., Garcia, F., De Sousa, V.S.R., Von Ranke, P.J., Rocco, D.L., Loula, G.D., De Carvalho, E.J., Gandra, F.C.G., (2009) Journal of Magnetism and Magnetic Materials, 321, p. 3014De Sousa, V.S.R., Carvalho, A.M.G., Plaza, E.J.R., Alho, B.P., Tedesco, J.C.G., Coelho, A.A., De Oliveira, N.A., Von Ranke, P.J., (2011) Journal of Magnetism and Magnetic Materials, 323, p. 794Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , (IoP - Institute of Physics Publishing UKRoss Jr., R.G., (2001) Cryocoolers, , (Kluwer Academic Publishers/Plenum Publishers New York, USANogués, J., Schuller, I.K., (1999) Journal of Magnetism and Magnetic Materials, 192, p. 203Koga, S., Narita, K., (1982) Journal of Applied Physics, 53, p. 1655Lacour, D., Jaffres, H., Dau, F.N.V., Petroff, F., Vaures, A., Humbert, J., (2002) Journal of Applied Physics, 91, p. 4655Daughton, J., Brown, J., Chen, E., Beech, R., Pohm, A., Kude, W., (1994) IEEE Transactions on Magnetics, 30, p. 4608Lenz, J., Edelstein, S., (2006) IEEE Sensors Journal, 6, p. 631Tsang, C., Fontana, R.E., Lin, T., Heim, D.E., Speriosu, V.S., Gurney, B.A., Williams, M.L., (1994) IEEE Transactions on Magnetics, 30, p. 3801Tsang, C., (1984) Journal of Applied Physics, 55, p. 2226Jensen, J., Mackintosh, A.R., (1991) Rare Earth Magnetism: Structures and Excitations, , Oxford University Press OxfordPurwins, H.G., Leson, A.A., (1990) Advances in Physics, 39, p. 309Swift, W.M., Wallace, W.E., (1971) Journal of Solid State Chemistry, 3, p. 180P.D. Kulkarni, S. Venkatesh, A. Thamizhavel, V.C. Rakhecha, S. Ramakrishnan, A.K. Grover, arXiv:0812.0929, (2008)Kulkarni, P.D., Thamizhavel, A., Rakhecha, V.C., Nigam, A.K., Paulose, P.L., Ramakrishnan, S., Grover, A.K., (2009) EPL (Europhysics Letters), 86, p. 47003Kulkarni, P.D., Dhar, S.K., Provino, A., Manfrinetti, P., Grover, A.K., (2010) Physical Review B, 82, p. 144411Von Ranke, P.J., De Oliveira, N.A., Alho, B.P., De Sousa, V.S.R., Plaza, E.J.R., Carvalho, A.M.G., (2010) Journal of Magnetism and Magnetic Materials, 322, p. 84Heimann, J., Kaczmarska, K., Kwapulińska, E., Ślebarski, A., Chełkowski, A., (1982) Journal of Magnetism and Magnetic Materials, 27, p. 187Lee, E.W., Montenegro, J.F.D., (1981) Journal of Magnetism and Magnetic Materials, 22, p. 282Webb, D.J., Marshall, A.F., Sun, Z., Geballe, T.H., White, R.M., (1988) IEEE Transactions on Magnetics, 24, p. 588Ovchinnikov, Y., Dyugaev, A., Fulde, P., Kresin, V., (1997) JETP Letters, 66, p. 195Ehrenreich, H., Seitz, F., Turnbull, D., (1969) Solid State Physics: Advances in Research and Applications, , Academic Press New YorkNereson, N., Olsen, C., Arnold, G., (1968) Journal of Applied Physics, 39, p. 4605Olsen, C.E., Arnold, G., Nereson, N., (1967) Journal of Applied Physics, 38, p. 1395Taylor, R.H., Coles, B.R., (1975) Journal of Physics F: Metal Physics, 5, p. 121Kwapulińska, E., Kaczmarska, K., Chelkowski, A., (1980) Acta Physica Polonica A, 58, p. 55

Heat Flow Measurements And The Order Of The Magnetic Transition In (dy,gd)co 2 Solid Solutions

In this work we present scanning heat flow measurements in the series of compounds Dy 1-xGd xCo 2 (x = 0, 0.1, 0.2, 0.3) which reveal a first order character in the magnetic transition for x = 0 and 0.1. The isothermal entropy change obtained for a magnetic field variation from 0 to 2T shows good agreement with the calculations based on a model Hamiltonian that takes into account the crystal field, magnetoelastic, exchange and Zeeman interactions. The maximum entropy change varies from 7.0 J/kg K (DyCo 2) to 1.8 J/kg K (Dy 0.7Gd 0.3Co 2) under a 2T magnetic field variation. The refrigerant cooling power (RCP) varies from 97 J/kg to 67 J/kg across the series. The entropy shows a strong correlation with the transition temperature regardless the transition type. © 2011 Elsevier B.V. All rights reserved.513615619Goto, T., Fukamichi, K., Sakakibara, T., Komatsu, H., (1989) Solid State Commun., 72, p. 945Goto, T., Sakakibara, T., Murata, K., Komatsu, H., Fukamichi, K., (1990) J. Magn. Magn. Mater., 9091, p. 700Duc, N.H., Brommer, P.E., (1999) Handbook of Magnetic Materials, 12, pp. 259-394. , Elsevier AmsterdamHerrero-Albillos, J., Casanova, F., Bartolome, F., Garcia, L.M., Labarta, A., Batlle, X., (2005) J. Magn. Magn. Mater., 290-291, p. 682Herrero-Albillos, J., Bartolome, F., Garcia, L.M., Casanova, F., Labarta, A., Battle, X., (2006) Phys. Rev. B, 73, p. 134410Khmelevskyi, S., Mohn, P., (2000) J. Phys. Condens. Matter., 12, p. 9453Liu, X.B., Altounian, Z., (2006) J. Phys. Condens. Matter., 18, p. 5503Liu, X.B., Altounian, Z., (2006) J. Appl. Phys., 99, pp. 08F709Balli, M., Fruchart, D., Gignoux, D., (2007) J. Magn. Magn. Matter., 314, p. 16Balli, M., Fruchart, D., Gignoux, D., (2008) J. Alloys Compd., 455, p. 73Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , first ed. Institute of Physics New YorkDe Oliveira, N.A., Von Ranke, P.J., (2010) Phys. Rep., 489, p. 89Wang, D., Liu, H., Tang, S., Yang, S., Huang, S., Du, Y., (2002) Phys. Lett. A, 297, p. 247Ouyang, Z.W., Rao, G.H., Yang, H.F., Liu, W.F., Liu, G.Y., Feng, X.M., Liang, J.K., (2003) Physica B, 334, p. 118Plackowski, T., Wang, Y., Junod, A., (2002) Rev. Sci. Instrum., 73, p. 2755Johnston, R.L., Hoffmann, R., (1992) Z. Chem., 616, p. 105Lea, K., Leask, M., Wolf, W., (1962) J. Phys. Chem. Solids, 23, p. 1382Stevens, K.W.H., (1952) Proc. Phys. Soc. Section A, 65, p. 209Wang, D.H., Tang, S.L., Liu, H.D., Gao, W.L., Du, Y.W., (2002) Intermetallics, 10, p. 819Gu, K., Li, J., Ao, W., Jian, Y., Tang, J., (2007) J. Alloys Compd., 441, p. 39Liu, X.B., Altounian, Z., (2005) J. Magn. Magn. Mater., 292, p. 83Alho, B.P., De Oliveira, N.A., De Sousa, V.S.R., Plaza, E.J.R., Magnus, A., Carvalho, G., Von Ranke, P.J., (2010) J. Phys.: Condens. Matter., 22, p. 486008Santana, R.P., De Oliveira, N.A., Von Ranke, P.J., (2011) J. Alloys Compd., 509, p. 6346Chen, X., Zhuang, Y.H., Yan, J.L., Fei, F., (2009) J. Alloys Compd., 479, p. 35Balli, M., Fruchart, D., Gignoux, D., (2011) J. Alloys Compd., 509, p. 3907Singh, N.K., Kumar, P., Suresh, K.G., Coelho, A.A., Gama, S., Nigam, A.K., (2007) J. Phys. D: Appl. Phys., 40, p. 162