Exchange interactions in barium hexaferrite -: art. no. 184433
Exchange interactions in barium hexaferrite -: art. no. 184433
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DOI：
10.1103/physrevb.71.184433
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发表时间：
2005-05-01
影响因子：
3.7
通讯作者：
Rusz, J
中科院分区：
文献类型：
--
作者：
Novák, P;Rusz, J
利用密度泛函理论和广义梯度近似（GGA）计算了BaFe12O19六铁体的电子结构。采用GGA+U方法改进了Fe强相关三维电子的描述。对一些自旋构型进行了计算。根据总能量的差异，确定了13个独立的交换积分作为参数U的函数，它们的大小随着U的增加而减小，表明反铁磁超交换起主导作用。利用分子场和随机相近似计算了居里温度T-C。由随机相位近似确定的T-C与U近似为6-7 eV时的实验T-C一致。
The electronic structure of BaFe12O19 hexaferrite is calculated using the density functional theory and generalized gradient approximation (GGA). The GGA+U method is used to improve the description of strongly correlated 3d electrons of Fe. The calculation is performed for a number of spin configurations. From differences of the total energies 13 independent exchange integrals are determined as functions of the parameter U. Their magnitude decreases with increasing U, pointing to the dominating role played by the antiferromagnetic superexchange. The Curie temperature T-C is calculated using the molecular field and the random phase approximations. T-C determined by the random phase approximation agrees with the experimental T-C for U approximate to 6-7 eV.