Specific heat and magnetic interactions in NdCrO3

The specific heat of NdCrO3 in the thermal range from 0.3 to 300 K is presented. The magnetic ordering of Cr ions at T-N=219+/-1K is observed, as well as the spin reorientation transition (SRT) at T-SRT=334.2 +/- 0.5 K. The specific heat of the isostructural nonmagnetic compound LaGaO3 has been subtracted, allowing us to separate and quantify the different magnetic contributions to the specific heat in NdCrO3. The exchange coupling constant for the Cr-Cr interaction is found to be \J(Cr)\/k(B) = 21.7(7) K. The fitting of the Schottky contribution from the thermal depopulation of the Nd3+ I-4(9/2) ground multiplet allows us to propose a crystal-field energy-level scheme which is in agreement with the available neutron-scattering spectral lines. The intensity of the Nd-Cr magnetic interaction is obtained. Finally, we show that the strength of the Nd-Cr interaction in this compound is of the same order of magnitude as that found in other Nd orthoperovskites, namely, in NdFeO3, despite the different Zeeman splitting of the Nd ground doublet in both compounds.