Stabilization of nanoscale magnetic bubbles in zero magnetic field by rotatable magnetic force microscopy.

The Stabilization of bubble magnetic textures in zero magnetic field has garnered significant attention due to its potential application in spintronic devices. Herein, we employed a home-built rotatable magnetic force microscopy (MFM) to observe the evolution of magnetic domains in NiO/Ni/Ti thin films. Magnetic stripe domains decay into isolated magnetic bubbles under an out-of-plane magnetic field at 100 K, and magnetic stripes reappear when the external magnetic field is reduced to zero. By rotating the sample within an external magnetic field of 0.42 T, the magnetic stripes transform into nanoscale magnetic bubble domains. This transition is driven by the minimization of the magnetostatic energy, accompanied by an increase in both the exchange energy and the Zeeman energy. The classical ferromagnetic Heisenberg model effectively describes the magnetic stripe-to-bubble transition under an applied magnetic field. The dense bubble domains remain stable in zero magnetic field due to long-range magnetostatic interaction. We introduce a straightforward method for constructing bubble domains in a zero magnetic field. This work presents a promising material platform for the future development of bubble-based spintronic devices.