Structure, magnetic, and thermal properties of Nd_1-xLa _xCrO₃ (0≤x≤1.0)

Perovskite-type Nd_1-xLa_x CrO₃ (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 Nd_1-xLa_x CrO₃ strongly depend on the La content. Two magnetic transition temperatures, Cr3+ antiferromagnetic ordering temperature (T_N) and the spin reorientation phase transition temperature (TSRPT), 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 Nd_1-xLa_x CrO₃ 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+ 3d t2g 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.