The Effect of Gd Substitution to the Dielectric and Optical Properties on MnFe2-xGdxO4

Abstract

In this work, we synthesized pristine and Gadolinium substituted MnFe2O4 and investigates their structural, electrical, and optical properties in detail. Pristine and Gd substituted spinel ferrite MnFe2-xGdxO4 (x = 0.00, 0.02, 0.04) were prepared via sol-gel method and resultant powder sintered at 5000 C for 5 hours in a high-temperature furnace. The phase of the obtained powder is identified using the Qualx 2.24 software. From the phase identification studies, it is confirmed that MnFe2-xGdxO4 (x = 0.00, 0.02, 0.04) exhibit spinel cubic structure. X-ray diffraction (XRD) studies were performed to explain the structure of these samples and it will discuss in detail. It was observed that the lattice parameter and cell volume of MnFe2O4 increase with Gd3+ substitution. It is also observed that the crystalline size first decreases and then increases with Gd substitution, however, the increase is less than that of pristine MnFe2O4. The hopping length of tetrahedral and octahedral sites increases with increasing Gd substitution. The variations in interionic interactions clearly show the strength of magnetic interactions. UV Visible spectroscopy studies were also carried out to understand the optical properties of pristine and Gd substituted samples. The estimated direct band gap values were decreasing with an increase in Gd substitution and exhibited an inverse relationship with Urbach energy. The dielectric spectroscopy of MnFe2-xGdxO4 (x = 0.00, 0.02, 0.04) was studied at frequencies ranging from 500 Hz to 1MHz which will explain the electrical properties of this material. The study reveals that dielectric permittivity increases with Gd substitution and dielectric loss are inversely related to Gd substitution.