Atomic Structure and Electron Magnetic Circular Dichroism of Individual Rock Salt Structure Antiphase Boundaries in Spinel Ferrites
Atomic Structure and Electron Magnetic Circular Dichroism of Individual Rock Salt Structure Antiphase Boundaries in Spinel Ferrites
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DOI：
10.1002/adfm.202008306
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发表时间：
2021-03-17
影响因子：
19
通讯作者：
Zhong, Xiaoyan
中科院分区：
文献类型：
--
作者：
Li, Zhuo;Lu, Jinlian;Zhong, Xiaoyan
尖晶石铁氧体是一类重要的材料，其磁性在工业应用中具有重要意义。尖晶石型铁氧体薄膜中普遍存在的反相晶界（APB）会影响材料的磁退化和磁电阻效应，从而阻碍其在自旋电子器件和传感器中的应用。然而，由于大多数磁成像技术的空间分辨率有限，将单个APB中的磁性与原子结构相关联是具有挑战性的。在这里，像差校正的扫描透射电子显微镜和电子能量损失磁性手性二色性被用来测量的原子结构和电子磁性圆二色性（EMCD）的单个APB在NiFe 2 O 4采取的形式的岩盐结构夹层，并与晶体平移（1/4）[011]。第一性原理密度泛函理论计算被用来确认，这个特定的APB引入反铁磁耦合和磁矩的大小，这是一致的，在APB的EMCD信号的观察到的减少显着减少。结果提供了新的洞察力的物理起源磁耦合在一个单独的缺陷上的原子尺度。
Spinel ferrites are an important class of materials, whose magnetic properties are of interest for industrial applications. The antiphase boundaries (APBs) that are commonly observed in spinel ferrite films can hinder their applications in spintronic devices and sensors, as a result of their influence on magnetic degradation and magnetoresistance of the materials. However, it is challenging to correlate magnetic properties with atomic structure in individual APBs due to the limited spatial resolution of most magnetic imaging techniques. Here, aberration-corrected scanning transmission electron microscopy and electron energy-loss magnetic chiral dichroism are used to measure the atomic structure and electron magnetic circular dichroism (EMCD) of a single APB in NiFe2O4 that takes the form of a rock salt structure interlayer and is associated with a crystal translation of (1/4)a[011]. First principles density functional theory calculations are used to confirm that this specific APB introduces antiferromagnetic coupling and a significant decrease in the magnitude of the magnetic moments, which is consistent with an observed decrease in EMCD signal at the APB. The results provide new insight into the physical origins of magnetic coupling at an individual defect on the atomic scale.