Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn0.99Co0.01As.

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