多铁材料BiNi_xFe_(1-x)O_3(x=0～0.5)磁性的第一性原理计算

First-Principles Calculation on Magnetism of Multiferroic Materials BiNi_xFe_(1-x)O_3(x=0—0.5)

采用基于密度泛函理论的第一性原理计算多铁材料BiNi_xFe_(1-x)O_3(x=0,0.125,0.167,0.25,0.5)各晶体结构的电子性质.能带结构、Mulliken电荷以及自旋磁矩等计算结果表明:由Ni离子部分替代掺杂Fe离子可使体系由反铁磁有序转变为局部亚铁磁有序,晶体总自旋磁矩随Ni离子浓度的增大而增大;Ni离子掺杂明显抑制了特定位置Fe离子的磁矩,这是由于Ni-eg轨道少数自旋方向的电子态被50%占据以及Ni离子与Fe离子之间的超交换作用所致.

We calculated the electronic properties of the crystal structures of multiferroic materials BiNi_xFe_（1-x）O_3（x=0,0.125,0.167,0.25,0.5）using the first-principles based on density functional theory.Calculation results of band structures,Mulliken charges and spin magnetic moments show that partial doping of Fe ions by Ni ions can make the system change from antiferromagnetic order to local ferrimagnetic order,and the total spin magnetic moments increase with the increase of concentration of Ni doping.Ni doping significantly inhibits the magnetic moment of Fe ions at specific sites,this is due to the electronics states of minority spin of Ni-egorbitals occupied by 50% and the superexchange interaction between Fe and Ni ions.