Date of Award
Master of Science
Sanjay R Mishra
Muhammad Shah Jahan
The (Sr,Ba) M-type hexagonal ferrites are important permanent magnetic materials for industrial applications. These ferrites possess relatively large saturation magnetization, high intrinsic coercivity, and high magnetic anisotropy field as well as excellent chemical stability and corrosion resistivity. Many studies have focused on cationic substitutions and on ionic radius considerations, such as rare-earths to further enhance ferrite magnetic properties. The present study highlights synthesis and characterization of rare-earth doped BaFe12O19 with an intention of improving overall magnetic properties of these ferrites. The effect of partial substitution of Ba+2 ion with RE+3 (RE= La, Pr, Nd, Sm and Gd) on magnetic properties of Ba-Ferrite prepared by solid state reaction using oxalate precursors is assessed in this study.The phase and structural analysis of as prepared sample shows formation of pure hexagonal phase micron size Ba-Ferrite particles. Ba-Ferrites show hard magnetic properties with Hc ~ 2.2 kOe and unsaturated Ms of 37 emu/g. However, except for the Pr+3 ion doping overall reduction in magnetic properties have been observed upon rare-earth ion doping. Concomitants reduction in Curie temperature is also observed in rare-earth doped Ba-Ferrites. Effect of replacing Ba+2 ion with dual RE+3 ions (Pr, and La) is on magnetic properties of Ba-Ferrite is also assessed. The change in magnetic properties upon rare-earth ion substitution in Ba-Ferrite is explained on the basis of crystal structure, super exchange interaction, rare earth single ion anisotropy, and iron site occupancy.
dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Lamichhane, Madan, "Synthesis and Magnetic Characterization of Rare-Earth Doped Barium-Ferrites" (2011). Electronic Theses and Dissertations. 309.