Optimization of the magnetic field of perpendicular ferromagnetic thin films for device applications

Abstract
We studied the geometrical factors controlling the magnitude of the demagnetizing field and the fringing fields of ferromagnetic thin films with perpendicular, out-of-plane magnetization. The magnetic field emerging from the patterned ferromagnetic thin film can interact with carriers in an underlying semiconductor structure and generate a Hall voltage. Different geometries for use in practical device applications have been analyzed, using a simplified model as a design tool. The optimum geometry of the ferromagnetic thin film that will give maximum magnetic-field strength in the underlying semiconductor consists of a grating-type structure with periodicity of a few 100 nm to 1 μm. These geometries are suited for realization by holographic lithography.