氧分压对Zn1-xCoxO1-δ磁性半导体磁特性的调控作用

OXYGEN PARTIAL PRESSURE MODULATION EFFECT ON THE FERROMAGNETISM OF Zn_(1-x)Co_xO_(1-δ) MAGNETIC SEMICONDUCTOR

利用电子显微分析技术对高Co含量的室温铁磁性半导体Zn_(1-x)Co_xO_(1-δ)进行了微观表征.证明了氧含量是决定Zn_(1-x)Co_xO_(1-δ)薄膜微观结构和磁性能的重要因素.在缺氧环境下,薄膜由含有大量氧缺位的纤锌矿结构的Zn_(1-x)Co_xO_(1-δ)纳米晶(直径约5 nm)和填充其间的Zn-Co-O非晶相组成,两相对薄膜宏观磁性均有贡献;在富氧的环境下,非晶Zn-Co-O相消失,出现了CoO反铁磁相,纤锌矿结构Zn_(1-x)Co_xO_(1-δ)中的氧缺位大量减少,晶粒长大到10—20 nm,室温铁磁性逐渐减弱,直至消失.

The microstructure of the room temperature ferromagnetic semiconductor Zn1-xCoxO1-δwas investigated by analytical electron microscopy.The experimental results indicated that the oxygen content decided the microstructure and the magnetic property of Zn1-xCoxO1-δThe films deposited under poor oxygen consist of 5 nm sized wurtzite Zn1-xCoxO1-δand amorphous Zn-Co-O between them,of which both are ferromagnetic phases.The films deposited under rich oxygen consist of 10—20 nm Zn1-xCoxO1-δand antiferromagnetic phase CoO,the concentration of the oxygen vacancy in wurtzite is greatly reduced,and the room temperature ferromagnetism is greatly weakened and even disappeared.