Structure, magnetic, and thermal properties of Nd1-xLaxCrO3 (0≤x≤1.0)

Perovskite-type Nd1-xLaxCrO3 (0 <= x <= 1.0) polycrystalline samples were synthesized using solid state reaction. Structural studies indicate that the lattice parameters, metal-oxygen bond lengths, and angles of Nd1-xLaxCrO3 strongly depend on the La content. Two magnetic transition temperatures, Cr3+ antiferromagnetic ordering temperature (T-N) and the spin reorientation phase transition temperature (T-SRPT), have been observed in the M-T curves. The increase in T-N and decrease in TSRPT with increasing x value can be explained by the change in the magnetic interactions due to La doping. The heat capacity of Nd1-xLaxCrO3 measured from 2 to 300 K reveals that the lattice, electronic, and magnetic contributions to heat capacity can be well interpreted quantitatively using the Debye and Schottky models. The splitting energy of the Cr3+ 3dt(2g) orbital and the Nd3+ ground state have been calculated by fitting to the Schottky anomaly at very low temperature. The Cr-Nd interaction is suppressed gradually by La doping, which is verified by the calculation of the mean-field interaction parameter. This doping dependence provides directed evidence of TM-RE magnetic interactions in perovskite compounds, in agreement with the proposed model. (C) 2010 American Institute of Physics. [doi:10.1063/1.3505800]