Specific heat and magnetocaloric studies of hexagonal Yb < inf > 1-x < /inf > Er < inf > x < /inf > MnO < inf > 3 < /inf >

Abstract

Specific heat CP of polycrystalline hexagonal Yb1-xErxMnO3 (x=0.1 and 0.2) samples is measured over a temperature range 2-160 K in different magnetic fields. From the Schottky analysis, Estimated effective molecular fields Hmf are 3.3 and 3.0 T for samples with x=0.1 and 0.2, respectively, in zero field. Maximum values of δSMmax are found to be 2 J mol-1 K-1 for Yb0.9Er0.1MnO3 and 2.1 J mol-1 K-1 for Yb0.8Er0.2MnO3, with 8 T field change in the vicinity of ferromagnetic ordering temperature of Yb3+. The values of adiabatic temperature change and relative cooling power are calculated to be 5.4 K, 23.1 J mol-1 and 5.6 K, 23.8 J mol-1 with a field change of 8 T for Yb0.9Er0.1MnO3 and Yb0.8Er0.2MnO3, respectively, which are appreciable enough to consider these samples as magnetic refrigerants at low temperature.