Relationship between coercivity and deposition conditions of Ba ferrite films prepared by facing targets sputtering apparatus

Abstract

At first, Ba ferrite films were deposited by the facing targets sputtering apparatus and the control of their coercivity was examined by substituting Fe 3+ ions to Ni 2+(F −) and Al 3+ ones and by changing crystallite size. The critical temperature for c-axis orientation T crit increased with increase of the substitution content x for both of BaO·6((1− x)Fe 2O 3· xNi 2OF 2) and BaO·6((1− x)Fe 2O 3· xAl 2O 3) films. The perpendicular coercivity H c⊥ of Ni 2+(F −) substituted Ba ferrite films decreased and that of Al 3+ substituted ones increased with increase in x and were about 0.32 and 3.3 kOe, respectively, at x of 0.17. Next, Ba ferrite films were deposited on Pt(1 1 1) underlayers and then, post-annealed at 800°C in air for 15 min. The value of H c⊥ corresponds to the crystallite size at T s up to 450°C. It has been founded that H c of BaM films were adjustable by substituting Fe 3+ ions to others such as Ni 2+(F −) and Al 3+ ions, and by controlling the crystallite size.