Studies on substituted Li-Mg-Fe spinels for microwave applications

Abstract

Studies carried out on substituted Li-Mg-Fe spinel compositions are reported here. The samples with chemical formula Li_0.5-(x-t)/2Mg_x-2Zn_zTi_tMn_aFe_{2.5−α−(x+3t)/2}O₄ with x = t = 0.55, α − 0.1 and z varying from 0 to 0.25 were prepared by ceramic method To obtain dense samples (> 96% X-ray densities) a small amount of Bi₂O₃ was added as a sintering aid. Zinc content enhances the saturation magnetisation. Resonance linewidth reduced from 230 Oe to 100 Oe with zinc level changing from 0 to 0.25. The dielectric constant value does not change much with z and the loss tangent was found to be < 0.0005 in the microwave frequency range. The accompanying effects on other magnetic properties of importance are also discussed.