Localized creation of bubble domains in Fe₃GaTe₂ by conductive atomic force microscopy

This study demonstrates the localized creation of bubble domains in the two-dimensional (2D) ferromagnetic material Fe₃GaTe₂ using conductive atomic force microscopy. By applying bias voltage to the tip under a perpendicular magnetic field, sufficient current is generated to induce localized Joule heating, transforming random stripe domains into bubble domains. The bubble domains were successfully induced under ambient conditions at room temperature and remained stable, as confirmed by magnetic force microscopy. For Fe₃GaTe₂ layers with thicknesses of 1 μm, 200 nm, and 100 nm, the average diameters of bubble domains were measured at 620 ± 100 nm, 325 ± 80 nm, and 230 ± 70 nm, respectively, approximately 20 % larger than the pristine stripe width. By optimizing parameters such as bias voltage, application duration, and tip temperature based on Fe₃GaTe₂ thickness, the induced bubble domain density could be precisely controlled, ranging from few bubble domains within areas < 5 μm² to nearly 10⁴ bubble domains within 1200 μm². Furthermore, multi-point triggering demonstrated the re-writability of the domain structures, with non-overlapping domains remaining unaffected. These findings offer critical insights into the tunability of magnetic textures in 2D ferromagnets, providing a foundation for developing next-generation spintronic devices based on 2D heterostructures.