Tunable magnetocaloric effect around room temperature by Fe doping in Mn0.98Cr(0.02-x)FexAs compound

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:436

Article

Ipus, Jhon J.¹  Ribeiro, Paula O.²  von Ranke, P.²  Caraballo Vivas, R. J.³  Carvalho, Alexandre M. G.⁴  Coelho, Adelino A.⁵  Franco, Victorino¹  Rocco, Daniel L.^3,6 

[1] Sevilla Univ, ICMSE CSIC, Dept Condensed Matter Phys, Seville 41080, Spain

[2] Univ Estado Rio De Janeiro, Inst Fis Armando Dias Tavares, Rua Sao Francisco Xavier 524, BR-20550013 Rio De Janeiro, RJ, Brazil

[3] Univ Fed Fluminense, Inst Fis, Av Gal Milton Tavares de Souza S-N, BR-24210346 Niteroi, RJ, Brazil

[4] CNPEM, Lab Nacl Luz Sincrotron, BR-13083970 Campinas, SP, Brazil

[5] Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, Caixa Postal 6165, BR-13083970 Campinas, SP, Brazil

[6] Ctr Fed Educ Tecnol Minas Gerais CEFET MG, Dept Formacao Geral, Campus Timoteo, BR-35180008 Timoteo, MG, Brazil

关键词: Magnetocaloric effect;    MnAs and derivatives;    Magnetic entropy change;    Composite;   

DOI  :  10.1016/j.jmmm.2017.04.030

来源: Elsevier

【 摘 要 】

In this work, we present an investigation of the magnetic and magnetocaloric properties of Mn0.98Cr((0.02-x))FexAs compounds with x = 0.002, 0.005 and 0.010. Our findings show that as Fe content increases the unit cell volume decreases, which indicates that Fe doping emulates the pressure effect on the crystalline structure. The transition temperature T-C decreases as x increases and it can be set at approximate value of room temperature by changing the doping level. In addition, the magnetic entropy change Delta S-M was determined using a discontinuous measurement protocol, and realistic values from the magnetocaloric effect presented by MnAs-type compounds under pressure (emulated pressure) could be obtained. The values of Delta S-M(MAX) are very large, around -11 J kg(-1) K-1 with Delta H = 15 kOe, which is higher than that observed for most compounds with TC around room temperature. However, Delta S-M is confined to a narrow temperature range of 11 K. To overcome this drawback, the composition of a theoretical composite formed by our samples was calculated in order to obtain a table-shaped Delta S-M curve. The simulated composite showed a high value of full width at half maximum delta T-FWHM of 33 K, which is much higher than that of single sample. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

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