Investigating Magnetic, Magnetodielectric, and Structural Properties of Sc-Substituted Hexagonal LuFeO3

Abstract

In this work, we investigated the structural, magnetodielectric, and magnetic properties of scandium-substituted hexagonal LuFeO₃. The Lu_0.33Sc_0.67FeO₃ (LSFO) compound stabilizes in a hexagonal structure (metastable) after synthesis by the sol–gel technique. The phase purity was confirmed by powder X-ray diffraction and neutron diffraction at room temperature. X-ray photoelectron spectroscopy (XPS) studies confirm the 3+ oxidation states of Lu, Sc, and Fe. The temperature-dependent magnetic data in the higher temperature range (180–300 K) fit well with the Curie–Weiss law, indicating paramagnetic behavior. Below 175 K, inverse susceptibility deviates from the fit due to magnetic ordering, which is the magnetic ordering temperature of LSFO. According to several research studies, the magnetic ordering temperature (T_N) in h-R(Fe/Mn)O₃ depends on the c/a ratio, with T_N increasing as the c/a ratio rises. In the title compound, we found the c/a ratio to be 2.008, the highest in the R(Fe/Mn)O₃ family, giving rise to the highest magnetic ordering temperature. The high negative Weiss temperature (−867 K) indicates a dominant antiferromagnetic interaction and frustration in the system. In the vicinity of 100 K, LSFO exhibits a weak ferromagnetic moment with a small loop opening in the M – H data. The dielectric constant has a little hump at the magnetic ordering temperature (175 K). The temperature versus dielectric constant data below 90 K at 0 and 7 T suggest that the dielectric constant depends on the external magnetic field, thus confirming magnetodielectric coupling in the system. We have observed up to a 1.5% magnetodielectric effect in LSFO.