UC Davis

Developing next-generation computing devices based on spintronics and magnonics requires understanding how spin textures can be tailored in patterned magnetic materials. Lithographically patterned micro/nanostructures can provide insights into the formation of magnetic domains consisting of flux closure states that are potential building blocks of magnetic memory. Complex oxides such as epitaxially grown La0.7Sr0.3MnO3 (LSMO) thin films exhibit strong correlations among spin, orbital, charge, and lattice degrees of freedom. As a soft ferromagnet, LSMO is a promising material for analyzing complex spin textures and controlling domain configurations by varying the micromagnet geometry. Using x-ray photoemission electron microscopy, thermally demagnetized LSMO donuts i.e., circular micromagnets with variable hole diameters, were imaged. The combination of quantitative image analysis and micromagnetic simulations allows probing and explaining the formation of spin textures consisting of either a single vortex or a pair of concentric vortices with opposite chirality in the donut structures. The results presented in this research are a step towards furthering our understanding of magnetic spin texture formation and vortex dynamics for developing spin-based devices.