The results from direct and indirect determinations of the magnetocaloric parameters of Mn0.99Co0.01As have been analyzed. The isothermal entropy change (ΔST) 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 (ΔTS) has been obtained from direct measurements and from isofield heat capacity measurements. The different results of both ΔST and ΔTS 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, −ΔST,max = 32.1 J/kg·K and ΔTS,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.

Trabajo presentado a: JEMS 2013 – Joint European Magnetic Symposia.-- This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0.

This work was supported by the Spanish MICINN and FEDER, projects MAT2007-61621 and CSD2007-00010. G.F. Wang acknowledges the Spanish CSIC for a predoctoral JAE grant.

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