Dielectric, magnetic and magnetoelectric studies of lithium ferrite synthesized by solid state technique for wave propagation applications

Abstract

The electric and magnetic properties of a lithium ferrite (LF) synthesized using the solid state reaction technique have been reported. The XRD studies reveal the cubic nature, from which the crystallite size and the lattice constant are determined to be 16.84 nm and 2.847 Å repectively. The FESEM confirms the coarseness in the samples with a low porosity. Variations of the dielectric constant and dielectric loss with temperature at different frequencies have been studied. The dielectric constant increases more steeply in the negative direction with increasing temperature beyond 500 °C at 100 kHz. The impedance plot exhibits almost complete semicircles at all temperatures, whose centers situated on the real axis. This suggests that the sample obeys the Debye behavior. The magnetic studies reveal a soft magnetic characteristic of LF. The ME voltage coefficient decreases with increasing magnetic field and attains a constant value in the high magnetic field. Keywords: Li0.5Fe2.5O4, XRD, Dielectric constant, Impedance spectroscopy, Magnetic transition temperature, ME coefficient