Magnetocaloric effects in MnFeP1-xAsx-based compounds

Here we present the results of an investigation of some magnetic and thermal properties of the compounds MnFeP0.45As0.55, MnFeP0.47As0.53, and Mn1.1Fe0.9P0.47As0.53 which can be regarded as possible magnetic refrigerants for room temperature applications. Magnetization measurements are performed in the temperature range 250-330 K, in magnetic fields up to 5 T. The coexistence of the magnetic and structural first-order phase transitions is revealed in all three samples, suggesting its key role in the large values observed for the magnetocaloric effect. The adiabatic temperature change measured directly was up to 4.0, 3.4, and 4.2 K for a magnetic field change of 1.45 T. (c) 2004 Elsevier B.V. All rights reserved.