Effects of grain isolation on magnetic properties of c-axis uniaxially in-plane oriented barium hexaferrite thin films

Magnetic properties of c-axis uniaxially in-plane aligned Ba-ferrite thin films were studied. Ba-ferrite thin films on [110] a-plane single-crystal sapphire substrates were deposited by low-power RF diode sputtering. Different degrees of grain isolation were achieved via postdeposition annealing at various temperatures in a rapid thermal annealing furnace. In this study, a magnetic evaluation of intergranular interaction was carried out using the well-established remanent magnetization ΔM curve. The results presented indicate a positive magnetostatic interaction, the strength of which is correlated with grain separation when measured along the magnetic easy axis direction. A predominant negative magnetostatic interaction was observed when measured along the magnetic hard axis direction, the magnitude of which is relatively independent of further grain separation