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The atomic and electronic structures of La0.7Sr0.3MnO3 (LSMO)/La0.7Sr0.3CrO3 (LSCO) multilayer thin films are investigated using aberration corrected scanning transmission electron microscopy (STEM) imaging and spectroscopy. Atomic resolution high angle annular dark-field reveals that LSMO layers have an expanded out-of-plane lattice parameter compared to compressed LSCO layers, contrasting with x-ray diffraction measurements. The expansion is found to result from preferential oxygen vacancy formation in LSMO during STEM sample preparation as determined by electron energy-loss spectroscopy. The La/Sr atom column intensity is also found to oscillate by about 4% between the LSMO and LSCO layers, indicative of La/Sr concentration variation. Using energy-dispersive x-ray spectroscopy in combination with image simulations, we confirm the La/Sr inhomogeneity and elucidate the origin of charge redistribution within the multilayer. These results illuminate the sensitivity of the technique to subtle structural, chemical, and electronic features that can arise to compensate charge imbalances in complex oxide heterostructures.
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This content will become publicly available on November 12, 2025
Oxygen Vacancy Effects in the Electronic and Magnetic Structure of La0.7Sr0.3MnO3 Epitaxial Thin Films from First Principles
La0.7Sr0.3MnO3 (LSMO) is a promising material for spintronic applications due to its robust ferromagnetism and complete spin polarization. However, these properties are known to degrade in thin films. Oxygen vacancies are believed to be a critical factor in this degradation, but experimentally isolating their effects has proven challenging. In this work, we use first-principles calculations to theoretically investigate how oxygen vacancies affect the magnetic structure of LSMO thin films. Our results reveal that oxygen vacancies act as scattering centers, leading to charge redistribution within the bulk layers. This redistribution disrupts the ferromagnetic double-exchange interaction and introduces competing super-exchange interactions, causing local spin flipping and ultimately reducing the overall magnetization.
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- Award ID(s):
- 2117575
- PAR ID:
- 10566312
- Publisher / Repository:
- SSRN
- Date Published:
- Journal Name:
- Social Science Research Network
- ISSN:
- 1556-5068
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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