Specific heat and magnetic interactions inNdCrO3

Abstract

The specific heat of ${\mathrm{NdCrO}}_{3}$ in the thermal range from 0.3 to 300 K is presented. The magnetic ordering of Cr ions at ${T}_{N}=219\ifmmode\pm\else\textpm\fi{}1\mathrm{K}$ is observed, as well as the spin reorientation transition (SRT) at ${T}_{\mathrm{SRT}}=34.2\ifmmode\pm\else\textpm\fi{}0.5\mathrm{K}.$ The specific heat of the isostructural nonmagnetic compound ${\mathrm{LaGaO}}_{3}$ has been subtracted, allowing us to separate and quantify the different magnetic contributions to the specific heat in ${\mathrm{NdCrO}}_{3}.$ The exchange coupling constant for the Cr-Cr interaction is found to be $|{J}_{\mathrm{Cr}}|{/k}_{B}=21.7(7)\mathrm{K}.$ The fitting of the Schottky contribution from the thermal depopulation of the ${\mathrm{Nd}}^{3+}{}^{4}{I}_{9/2}$ 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 ${\mathrm{NdFeO}}_{3},$ despite the different Zeeman splitting of the Nd ground doublet in both compounds.