(Bi,A）FeO₃薄膜（A ＝Ca,Sr,Ba（アルカリ土類金属））の結晶構造と磁気特性におよぼすレーザーアシスト加熱成膜・後アニールの効果

抄録

High saturation magnetization is required for BiFeO₃-based multiferroic（ferromagnetic/ferroelectric）thin films to apply magnetic writing element of Racetrack Memory which is a nextgeneration magnetic recording device. A newly introduced laser-assisted heating system was used to form high quality（Bi, A）FeO₃（A=Ca, Sr, Ba（alkaline earth metal））thin films. The maximum substrate temperature was increased from 695 to about 858℃ by using this laserassisted heating system combining with lamp heating system of sputtering equipment. In the case of（Bi, Ca）FeO₃ and（Bi, Sr）FeO₃ with the Ca or Sr substitution concentration of 50～ 60 at％ fabricated by using the laser-assisted heating system, the crystallinity was improved, but oxygen vacancy could not be suppressed. As the result, saturation magnetization was not large. In the case of（Bi, Ba）FeO₃ with the Ba substitution concentration of 50～60 at％ fabricated by using the laser-assisted heating system, oxygen vacancy could be suppressed. As the result, highest saturation magnetization of around 100 emu/cm³ was obtained in（Bi, Ba）FeO₃ thin films.