Orientation Growth and Magnetic Properties of BaM Hexaferrite Films Deposited by Direct Current Magnetron Sputtering

In‐plane c‐axis oriented Ba‐hexaferrite (BaM) thin films were prepared on a‐plane sapphire (Al₂O₃) substrates using direct current (DC) magnetron sputtering followed by ex‐situ annealing. The sputtering atmosphere was found to have a great influence on the stoichiometry, orientation growth, and grain morphology of the as‐prepared BaM films. With moderate oxygen partial pressure during sputtering, in‐plane c‐axis highly oriented BaM films were obtained. The films showed strong magnetic anisotropy with a high hysteresis loop squareness (M_r/M_s of 0.96) along in‐plane easy axis and a low M_r/M_s of 0.05 along in‐plane hard axis. Rocking curves and pole figures were utilized to reveal the epitaxial‐like orientation relationship of the BaM films relative to the sapphire substrates, as well as the orientation growth dispersion of the hexagonal platelet‐shaped grains in BaM films.