Atomic origin of magnetic coupling of antiphase boundaries in magnetite thin films
Atomic origin of magnetic coupling of antiphase boundaries in magnetite thin films
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DOI：
10.1016/j.jmst.2021.08.017
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发表时间：
2021-10
影响因子：
10.9
通讯作者：
Chunyang Gao;Yixiao Jiang;Ting-ting Yao;Ang Tao;Xuexi Yan;Xiang Li;Chunlin Chen;Xiu-Liang Ma;H. Ye
中科院分区：
文献类型：
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作者：
Chunyang Gao;Yixiao Jiang;Ting-ting Yao;Ang Tao;Xuexi Yan;Xiang Li;Chunlin Chen;Xiu-Liang Ma;H. Ye
揭示边界缺陷的磁耦合性质对于深入理解磁性材料和器件的行为和性质至关重要。采用脉冲激光沉积法在（100）SrTiO 3单晶衬底上外延生长了Fe 3 O 4薄膜。原子尺度的扫描透射电子显微镜表征表明，在Fe 3 O 4薄膜中形成了三种类型的反相界（APBs）。它们是在（100）平面上以（1/4）a [01 1 <$]的晶体平移形成的（100）APB，I型和II型（110）APB都在（110）平面上以相同的（1/4）a [101]晶体平移形成，但终止原子平面不同。I型（110）APB终止于四面体和八面体混合位Fe原子的原子面，II型（110）APB终止于八面体位Fe原子的原子面。第一性原理计算表明，（100）型和I型（110）型APB倾向于形成铁磁耦合，但不会降低Fe 3 O 4薄膜的自旋极化，而II型（110）型APB倾向于形成反铁磁耦合，但会降低Fe 3 O 4薄膜的磁性. APBs的磁耦合模式与边界上的Fe-O-Fe键角密切相关。
Revealing the magnetic coupling nature of boundary defects is crucial for in-depth understanding of the behavior and properties of magnetic materials and devices. Here, magnetite (ie, Fe 3 O 4) thin films were grown epitaxially on (100) SrTiO 3 single-crystal substrates by pulsed laser deposition. Atomic-scale scanning transmission electron microscopy characterizations reveal that three types of antiphase boundaries (APBs) are formed in the Fe 3 O 4 thin film. They are the (100) APB that is formed on the (100) plane with a crystal translation of (1/4) a [01 1¯], the type I and type II (110) APBs that are both formed on the (110) plane with the same crystal translation of (1/4) a [101] but different terminated atomic planes. The type I (110) APB is terminated at the atomic plane with mixed tetrahedral-and octahedral-sites Fe atoms, the type II (110) APB is terminated at the octahedral-site Fe plane. First-principles calculations reveal that the (100) APB and the type I (110) APB tend to form the ferromagnetic coupling that will not decrease the spin polarization of Fe 3 O 4 films, while the type II (110) APB prefers to form the antiferromagnetic coupling that will degrade the magnetic properties. The magnetic coupling modes of the APBs are closely related to the Fe-O-Fe bond angles across the boundaries.