Abstract
We report the asymmetry of longitudinal magneto-optical Kerr loops obtained from diffracted spots of a NiFe grating. The analysis of several series of diffracted Kerr hysteresis loops reveals that the unsaturated magnetic structure not only contributes to the shape change of Kerr loops, but also results in asymmetric feature of Kerr loops because of the nonzero value of second-order magnetic response. A suitable pattern dimension, which defines the form factor, is helpful to observe asymmetry Kerr loops. Our experiment indicates that out-of-incidence-plane diffraction may offer an alternative method to observe lateral edge domain movements in patterns. (C) 2001 American Institute of Physics.