Variations from Zn1-xCoxO Magnetic Semiconductor to Co-ZnCoO Granular Composite  

作　　者：陈延学 颜世申 刘国磊 梅良模 任妙娟 

机构地区：[1]School of Physics and Microelectronics and National Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 [2]School of Science, Jinan University, Jinan 250022

出　　处：《Chinese Physics Letters》2007年第1期214-217,共4页中国物理快报（英文版）

基　　金：Supported by the National Basic Research Programme of China under Grant No 2001CB610603, the National Natural Science Foundation of China under Grant Nos 50402019 10234010 and 50572053, NCET040634 and the Doctoral Fund of Jinan University （B0404）.

摘　　要：We investigate the variations from as-deposited Zn1-x： Cox O magnetic semiconductors to the post-annealed Co- ZnCoO granular composite. The as-deposited Zn1-x Cox 0 magnetic semiconductor deposited under thermal nonequilibrium conditions is composed of Zn1-x. Cox O nanograins of high Co concentration. The room-temperature ferromagnetism with high magnetization and large negative magnetoresistance are found in the as-deposited samples. By annealing, the samples become of granular composite consisting of the Co metal grains and the remanent Zn1-x CoxO matrix. Although the magnetization is enhanced after annealing, the spin-dependent negative magnetoresistance disappears at room temperature. The magnetoresistance observed in the annealed samples in the high field region has no relation with the ferromagnetism, which in turn indicates that the roomtemperature ferromagnetism and large negative magnetoresistance observed in the as-deposited are the intrinsic properties of the Zn1-x Cox O magnetic semiconductor.We investigate the variations from as-deposited Zn1-x： Cox O magnetic semiconductors to the post-annealed Co- ZnCoO granular composite. The as-deposited Zn1-x Cox 0 magnetic semiconductor deposited under thermal nonequilibrium conditions is composed of Zn1-x. Cox O nanograins of high Co concentration. The room-temperature ferromagnetism with high magnetization and large negative magnetoresistance are found in the as-deposited samples. By annealing, the samples become of granular composite consisting of the Co metal grains and the remanent Zn1-x CoxO matrix. Although the magnetization is enhanced after annealing, the spin-dependent negative magnetoresistance disappears at room temperature. The magnetoresistance observed in the annealed samples in the high field region has no relation with the ferromagnetism, which in turn indicates that the roomtemperature ferromagnetism and large negative magnetoresistance observed in the as-deposited are the intrinsic properties of the Zn1-x Cox O magnetic semiconductor.

分 类 号：O44[理学—电磁学]