ASYMMETRIC MAGNETOOPTIC RESPONSE IN ANISOTROPIC THIN-FILMS

We report asymmetric hysteresis loops measured using the magneto-optic Kerr effect from epitaxial Fe(110) and Co(110) thin films with in-pla ne magnetic anisotropy. This asymmetry appears to violate the invarian ce of the hysteresis loop under the transformation M-->-M, H-->-H (M i s the magnetization and H is the applied field). The asymmetric magnet o-optic response is due to a product of the longitudinal and transvers e components of the magnetization and proves the existence of the tran sverse component of the magnetization and, therefore, of the coherent rotation model of magnetization reversal. We simulate the observed hys teresis loops with a term in the magneto-optic response second order i n the magnetization that is much larger than predicted by the standard magneto-optic theory.