Atomic Structure and Electron Magnetic Circular Dichroism of Individual Rock Salt Structure Antiphase Boundaries in Spinel Ferrites

Abstract

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 NiFe 2 O 4 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.

Influence of the cation distribution, atomic substitution, and atomic vacancies on the physical properties of CoFe2O4 and Ni<

“…experimentally on various compounds [74]. Our results for NFO are in agreement with former DFT studies [30,32,75], which however only compared a very small number of wellordered inverse spinel structures. The predicted lowest energy space group of NFO also corresponds to that measured at 300 K on single crystals with Raman spectroscopy [70] or with synchrotron diffraction [71].…”

Robust Ferrimagnetism and Switchable Magnetic Anisotropy in High‐Entropy Ferrite Film

“…[ 32,33 ] Recently, Li et al. [ 51 ] also confirmed that the antiferromagnetic coupling interaction in the APB defects weakens the magnetism based on electron magnetic circular dichroism measurements and first‐principles density functional theory calculations. To confirm the existence of the antiferromagnetic phase in HEO thin film, the M – H loops of IP at 10 K for the 60 nm thick film were collected under an applied magnetic field cool by 1000 Oe (Figure 4h).…”

Amplifying inorganic chirality using liquid crystals

“…The interactions between the stimulus and chiral components change the chirality, manifesting as the change of g-factor and g lum values. 78,79 Typically, CD and CPL spectra enable quantifying the degree of the stimulus. As presented in Fig.…”