Analysis of structural and magnetic phase transition behaviors of La 1− xSr xCrO 3 by measurement of heat capacity with thermal relaxation technique

Abstract

The heat capacity, C p , of the La 1− x Sr x CrO 3 system and its temperature dependence have been measured by a thermal relaxation technique. Both structural and magnetic phase transitions were detected at temperatures that can be surmised from the phase diagram proposed in previous studies. The observed variation in enthalpy after the first-order structural phase transition, Δ H, showed agreement with those measured by differential scanning calorimetry (DSC). A decrease in the variation in C p in the second-order magnetic phase transition, Δ C p , with an increase in Sr content was detected, which can be attributed to a decrease in electronic spin configuration entropy with an increase in Sr content. In the dependence of Δ C p on Sr content, a bending point was also observed at x ∼ 0.12, at which the crystal system varies from an orthorhombic-distorted perovskite structure to a rhombohedral-distorted perovskite structure.