Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn_0.99Co_0.01As

¹ Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
² Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, 014010 Baotou, China
³ Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-970, Campinas, Brazil
⁴ Universidade Federal de Sao Paulo, Diadema, São Paulo 00972-270, Brazil

^a Corresponding author: burriel@unizar.es

Published online: 3 July 2014

Abstract

The results from direct and indirect determinations of the magnetocaloric parameters of Mn_0.99Co_0.01As have been analyzed. The isothermal entropy change (ΔS_T) due to external magnetic field changes has been determined through direct measurements of the heat absorbed by the sample when the field is removed under isothermal conditions. It has also been calculated from isothermal magnetization and isofield heat capacity measurements. In addition to that, the adiabatic temperature change (ΔT_S) has been obtained from direct measurements and from isofield heat capacity measurements. The different results of both ΔS_T and ΔT_S are compared. Due to the presence of a first-order phase transition, the studied sample exhibits giant magnetocaloric effect at room temperature. The observed maximum values, −ΔS_T,max = 32.1 J/kg·K and ΔT_S,max = 17.7 K for a field change from 0 to 6 T, suggest that the Co-doped MnAs compounds are promising candidates for the preparation of useful materials for magnetic refrigeration near room temperature.