Magnetic and robust dielectric properties in distorted double perovskite Gd2CuTiO6

In this article, we describe our research on the structural, morphological, dielectric, and magnetic properties of Gd2CuTiO6. This compound was synthesized using solid state reaction. It crystallizes in orthorhombic structure with the space group Pnma. An estimation of compressive and tensile strain is made using the Bond Valence Sums calculation. Moreover, the compound exhibits disorder in the B-site octahedra, octahedral tilting (18.35° along b axis) and substantial distortion in bond lengths which supports the existence of orthorhombic distortion. Cu/Ti atoms located at the center of symmetry in the unit cell of Gd2CuTiO6 do not contribute to Raman modes. Nonetheless stretching and bending vibrations of Gd-O1/O2 bonds result in 24 Raman active modes. Gd2CuTiO6 has a moderate dielectric constant of 191 and a low dielectric loss of 0.42 at 100 Hz at ambient temperature. The activation energy calculated using the Arrhenius equation is 0.31 eV. Magnetic susceptibility measured from room temperature down to 4 K showed a paramagnetic trend without any long range ordering. A Curie–Weiss fit to inverse paramagnetic susceptibility yielded an effective magnetic moment of 11.5 μB. By taking into account the individual magnetic moments of Gd3+ and Cu2+ ions, theory predicts that the effective magnetic moment to be 11.3 μB. The results reveal a good agreement between the observed and the theoretical effective magnetic moments. Field dependence of magnetization, M(H) at different temperatures indicated a second order phase transition at applied fields greater than 1.2 T. Examination of M(H) curves using Brillouin function demonstrated the presence of a weak-ferromagnetic component below 20 K.