中文摘要：

采用广义梯度近似和哈伯德U的第一性原理计算方法,对YzCo1-xFe2O4（Y=Mg,Zn,Mn,x=0.00,0.25,0.50,0.75,1.00）系列体材料的电学与磁学性质进行了研究.研究发现：①八面体占位的CoB2＋高/低自旋态随原子掺杂比的不同可能发生转换;②高自旋态CoB2＋的磁矩随反转比的不同出现较大波动,其变化范围约为2.54～2.85μB;③对YxCo1-xFe2O4而言,当反转比x在0.75～1.00范围变化时,材料将发生半金属-绝缘体相变.

英文摘要：

Using generalized gradient approximation plus U method,we present electronic and magnetic properties through a systemic theoretical calculation of Yx Co1-x Fe2O4 （Y =Mg,Zn and Mn,x =0.00,0.25,0.50,0.75 and 1.00）.Our main results show that：① the octahedral CoB2＋ions may show high/low spin states under different doping concentration x; ② magnetic moments of high spin state for CoB2＋ can be changed by different doping degrees,it ranges from 2.54 μBto 2.85 μB ; ③ the spinel structure will change from metal to half-metal at the inversion degree region from 0.75 to 1.00.