Ni/BiFeO_3超晶格磁电效应的第一性原理计算

为了探究铁磁/铁电超晶格材料的磁电耦合效应,采用基于密度泛函理论的第一性原理计算方法,研究了Ni/BiFeO_3超晶格的电子结构和磁矩.结果表明,Ni/BiFeO_3超晶格界面处Ni-3d轨道与O-2p轨道发生了强烈的电子杂化作用,Ni和BiFeO_3界面主要通过以O原子为中间媒介的电荷转移进行相互影响.在外加电场作用下,由于铁电极化的存在,超晶格结构上下两个界面存在磁化差异,原子成键和电荷转移重新分布能够引起较强的磁电耦合效应. Ni/BiFeO_3超晶格界面磁电耦合系数约为3. 509×10-~(14)T·cm~2/V.

First-principle calculation for magnetoelectric effect of Ni/BiFeO3 superlattice

In order to investigate the magnetoelectric coupling effect of ferromagnetic/ferroelectric superlattice materials, the electronic structure and magnetic moment of Ni/BiFeO₃ superlattice were studied with the first-principle calculation method based on the density functional theory. The results show that the strong electronic hybridization effect of Ni-3d and O-2p orbitals occurs at the Ni/BiFeO₃ superlattice interface, and the Ni and BiFeO₃ interface interacts with each other mainly through the charge transfer mediated by O atoms. Under the effect of external electric field and due to the presence of ferroelectric polarization, the top and bottom interfaces of superlattice structure exhibit the magnetization difference. In addition, the atomic bonding and charge redistribution can give rise to the strong magnetoelectric coupling effect. The magnetoelectric coupling coefficient is obout 3.509×10^-14 T·cm²/V for the Ni/BiFeO₃ superlattice interface.