Scanning nonlinear magnetic microscopy

Scanning nonlinear magnetic microscopy (SNMM) is introduced as a new microscopic technique for measurement of the distribution of magnetization. The technique is based on the detection of inductance variation in a magnetic material under application of an external alternating magnetic field. The measured inductance thus reflects the nonlinear magnetic response of the material, giving the nonlinear magnetic permeability (μ333) and the direction and magnitude of magnetization. SNMM is demonstrated in application to measurement of the magnetization distribution of a floppy disk.