Mössbauer study of CoFeRhO4 Original Research Article

CoFeRhO4 has been studied by Mössbauer spectroscopy and X-ray diffraction. The crystal is found to have a cubic spinel structure with the lattice constant a0=8.451±0.005 Å. The iron ions are in ferric states. The temperature dependence of the magnetic hyperfine field is analyzed by the Néel theory of ferrimagnetism. The intersublattice superexchange interaction is antiferromagnetic and strong with a strength of JAB=−12.39kB while the intrasublattice superexchange interactions are weak with strengths of JAA=−4.96kB and JBB=6.20kB. As the temperature increases toward the Néel temperature TN, a systematic line broadening effect in the Mössbauer spectrum is observed and interpreted to originate from different temperature dependences of the magnetic hyperfine fields at various iron sites.