摘要
利用固态反应法合成了纯相的CuAlO2和过渡金属元素Co掺杂的CuAlO2样品。通过X射线衍射仪分析可知:未掺杂样品和1%(摩尔分数)Co掺杂的样品都是单相,其中没有CuO等杂相存在,而掺杂浓度分别为5%、10%和20%的样品中都出现了CuAlO2以外的杂相,这表明Co在CuAlO2粉体样品中的杂质固溶度一般低于5%。综合物性测试系统测得的与磁性有关数据表明:未掺杂及Co掺杂(1%)的纯相CuAlO2样品只具有顺磁性,而多相的Co掺杂样品从5～300K都没有表现出如第一性原理理论所预言的铁磁性,这说明样品中所掺入的Co离子只是具有局域磁矩的顺磁杂质中心,并不能形成长程的铁磁序,进一步表明基于第一性原理的理论计算可能高估了过渡金属磁性杂质在氧化物半导体这种关联体系中的铁磁耦合作用。
Undoped CuAIO2 and transition element cobalt doped CuA102 samples were synthesized by the solid state reaction method. Spectral analyzing by means of X-ray diffraction indicates that the undoped CuA102 and Co- doped （1 G mole ratio） samples are single phase, while other phases exist in the synthesized samples with the Co con- centrations increasing to 5%, 10% and 20%. The results indicate that the solubility of Co in CuA102 is generally less than 5%. The magnetic measurements indicate that single phase undoped and 1% Co-doped CuA102 samples are para- magnetic. Particularly, in the temperature range from 5K to 300K, none of the synthesized samples show ferromagne- tism predicted by the first-principles theory, demonstrating that the Co dopants are the paramagnetic impurity centers and there is no observable ferromagnetic coupling among them. These results indicate that the first-principles calcula- tions maybe overestimate the ferromagnetic interactions among the magnetic dopants in the strongly correlated oxide semiconductors.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2012年第22期31-34,共4页
Materials Reports
基金
国家自然科学基金(61076089
11175066)
