Structural, magnetic, dielectric and spectroscopic impedance analysis of magnesium iron oxide thin films synthesized by electrodeposition: Effect of preferred orientation

Abstract

Magnesium iron oxide is the most valuable and versatile spinel system with reduced eddy current and dielectric losses. Spinel ferrites are electrically non-conductive. The electrodeposition is used to synthesize thin films on Cu substrate. A set of five thin films is prepared by varying the in-situ oxidation time (10 min, 15 min, 20 min, 25 min and 30 min) and a fixed deposition time of 25 min. The x-ray diffractometer XRD (phase confirmation), Scanning Electron Microscope SEM (morphological analysis), Fourier transforms infra-red spectroscope FT-IR (bond-formation), impedance analyzer (dielectric-measurements) and vibratory sample magnetometer VSM (magnetic properties) has been utilized to examine the prepared samples. All the studied samples have been found, single-phase spinel structures. XRD shows the pure phase formation of spinel MgFe2O4 at 20 min, 25 min, and 30 min. The exchange of the preferred orientation (PO) from (731) mixed phase to (533) spinel is observed. This change in preferred orientation has been caused the changes in the properties of prepared thin films. The average lattice constant, cell volume, x-ray density and crystallite size of magnesium-iron oxide were found at 8.3814 Å, 588.58 (Å)3, 3.2098 g/cm3 and 24.0392 nm respectively. In FTIR analysis of magnesium-iron oxide, two characteristic spinel bands are observed below 700 cm−1. The SEM result showed a smooth granular structure at 30 min. The normal behavior of the dielectric constant and single semicircle is observed in cole-cole plot. All the prepared thin films are ferromagnetic in nature. At 30 min, a higher dielectric constant, 20.2 (log f = 5) and 162.3 emu/cm3 saturation magnetization. The remarkable dielectric and magnetic findings are promising for using electrodeposited thin films in electronic and spintronic devices.