Influence of rare earth ions (Sm3+, Dy3+) substitution on magnetic and microwave performance of magnesium ferrite

Abstract The nano-crystalline rare earth (Sm3+, Dy3+) substituted MgFe2O4 with composition Mg[(Sm)0.6(Dy)0.4]xFe2-xO4 [x varies from 0.0 to 0.3 in steps of 0.05] have been prepared by chemical combustion route. X-ray diffraction analysis confirmed the formation of the spinel cubic phase as a major phase along with the perovskite ortho-ferrite phase as a minor phase in all the samples except MgFe2O4. The room temperature magnetic properties of these samples have been investigated. It has been observed that with an increase in substitution of rare-earth ions (Sm3+, Dy3+), for iron in MgFe2O4, initial permeability increases, attain peak value for the composition with x = 0.15, and decreases for higher substitution concentrations. The microwave absorption performance of the Mg[(Sm)0.6(Dy)0.4]xFe2-xO4 systems have been investigated. The reflection coefficients are found to be higher as compared to MgFe2O4 whereas Voltage Standing Wave Ratio (VSWR) found to be lower. Overall investigations indicate Mg[(Sm)0.6(Dy)0.4]0.15Fe1.85O4 is a promising candidate for microwave device fabrication.