57Fe Mössbauer study of spin reorientation transition in polycrystalline NdFeO3

The present work reports the preparation of polycrystalline NdFeO3 using sol-gel method and characterization using X-ray diffraction (XRD), Raman spectroscopy, bulk magnetization, 57Fe Mössbauer spectroscopy and ferroelectric measurements. XRD and Raman spectroscopy measurements confirm the phase purity of the prepared sample. The temperature dependent magnetization measurement shows the signatures of spin re-orientation transition (TSRT) between 66 and 158 K and magnetic field induced transition at about 2.5 T and 5 K. It is observed from the low temperature (25-300 K) 57Fe Mössbauer measurements that the temperature variation of hyperfine parameters shows the signatures of TSRT. The observed area ratio of second and third line intensity (A23) in Mössbauer sextet, across TSRT, show deviations from the value characteristic of random spin orientation in polycrystalline sample. In addition, the quadrupole shift changes sign across TSRT indicating the spin-reorientation of Fe3+ ions. The room temperature leakage current density (J-E) measurements indicate that Ohmic contribution and space charge limited conduction are the dominating mechanisms at low and high applied electric fields, respectively, similar to that of other RFeO3 (R - rare earth) based compounds. Lossy ferroelectric loops were observed at room temperature.