The origin of the converse magnetoelectric (CME) effect in the Nb‐doped BaTiO₃ (NBTO) polar metal is investigated by density functional theory. Unlike the Fe doping system, where the magnetic moment is chiefly contributed by e_g orbitals of the Fe atom, the magnetic moment of the NBTO system is mainly contributed by the d_xz/d_yz orbitals of Ti (Nb) atoms and highly depends on the polarization intensity. When the in‐plane compressive strain η ≤ −2%, the magnetic moment of the NBTO system is zero because electrons predominantly occupy the d_xy orbitals. However, the switching process of the ferroelectric polarization induces a strong CME effect with significant magnetic moment changes. Especially, the magnetic moment changes in the NBTO system with the compressive strain η ≤ −2%, which is dozens of times of that of the unstrained NBTO system. These results are useful for designing new ultrafast and low‐power information storage devices with remarkable electrically controlled magnetism.

中文翻译：

---

Nb掺杂的BaTiO3基极性金属中强逆磁电效应的预测

通过密度泛函理论研究了Nb掺杂BaTiO ₃（NBTO）极性金属中逆磁电（CME）效应的起源。不同于铁掺杂系统，其中，所述磁矩主要贡献的Ë_克Fe原子的轨道，所述NBTO系统的磁矩主要贡献的d _XZ / d _YZ轨道的Ti（Nb）的原子数的和高度依赖于极化强度。当在面内压应变η  ≤-2％，所述NBTO系统的磁矩是零，因为电子主要占据d _XY轨道。但是，铁电极化的切换过程会产生强烈的CME效应，并且磁矩会发生明显变化。特别是，磁矩在NBTO系统与压缩应变的变化η  ≤-2％，这是几十个的该无应变NBTO系统的倍。这些结果对于设计具有卓越电控磁力的新型超快速和低功耗信息存储设备很有用。