Epitaxial strain tailoring of the antiferromagnetic/ferromagnetic oxide thin film properties
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video conference : https://univ-grenoble-alpes-fr.zoom.us/j/98769867024?pwd=dXNnT3RMeThjYStybGVQSUN0TVdJdz09
Meeting ID: 987 6986 7024
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Abstract : Antiferromagnetic (AF) oxide materials such as LaFeO₃ (LFO) are promising for spintronic applications due to their ultrafast spin dynamics, especially when their magnetic domain configurations and Néel axis orientations can be controlled. Bulk LFO exhibits a high Néel temperature (740 K) and a pseudocubic structure, making it a model system for exploring strain control of AF properties. Using oxide molecular beam epitaxy, we coherently grew stoichiometric LFO thin films on substrates spanning a wide range of compressive and tensile strains of various symmetries, and probed their AF domains with X-ray absorption spectroscopy varying light polarizations and coupled to a photoemission electron microscope.
We demonstrate that epitaxial strain dictates the Néel axis orientation: compressive strain favors in-plane alignment, whereas tensile strain drives out-of-plane orientation. Interestingly, monodomain AF configurations are stabilized on orthorhombic substrates, while cubic substrates induce fourfold multidomain structures—except when the strain is sufficiently large. Beyond epitaxial effects, strain relaxation via dislocations and defects locally reorients the Néel axis and can even reverse the XMLD contrast, revealing complex three-dimensional domain textures. Miscut substrates further break the growth symmetry, reducing the degeneracy of AF domains and, in some cases, stabilizing non-collinear monodomains.
When the AF layer is coupled to a ferromagnetic material, such as the archetypal La₁₋ₓSrₓMnO₃ (LSMO), we observe a spontaneous transfer of AF domain configurations into the F layer, leading to a spin-flop coupling. This strain-driven propagation enables fine-tuning of the entire heterostructure’s magnetic properties, allowing transitions between monodomain and multidomain coupling regimes.
Overall, these findings establish growth engineering as a powerful approach to control AF properties—and, by extension, ferromagnetic ones—through interfacial exchange coupling, opening new routes for technological applications.
V. Polewczyk et al., Control of the Antiferromagnetic Domain Configuration and Néel Axis Orientation with Epitaxial Strain, Commun. Mater. 6, 153 (2025)