Kerr imaging of a Co/Pt bimodal magneto-optical medium

Spatially resolved magneto-optical (MO) images of a (0.3 nm Co/1.2nm Pt)(15 ) multilayer film with perpendicular magnetic anisotropy have been obtained by Kerr microscopy. This material exhibits a major hysteresis loop with tw o-step magnetization reversal. The MO images display four possible "stable" magnetic states distinguished by four different intensities. This behavior is explained by the presence of two different magnetic phases each which h as a stable magnetization state either parallel or antiparallel to the appl ied field, and which may reverse quasi-independently from one another. (C) 1999 American Institute of Physics. [S0021-8979(99)22008-7].