Theoretical investigation on the magnetocaloric effect in MnAs using a microscopic model to describe the magnetic and thermal hysteresis

Abstract

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. (c) 2012 Elsevier B.V. All rights reserved.Univ Estado Rio de Janeiro, Inst Fis Armando Dias Tavares, BR-20550013 Rio de Janeiro, BrazilUnifesp, Dept Ciencias Exatas & Terra, BR-09972270 Diadema, BrazilUniv Estadual Campinas UNICAMP, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, BrazilInst Nacl Metrol Normalizacao & Qualidade Ind INM, Div Mat Metrol, BR-25250020 Duque de Caxias, RJ, BrazilUnifesp, Dept Ciencias Exatas & Terra, BR-09972270 Diadema, BrazilWeb of ScienceFundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP