Magnetic capping layer induced spin reorientation: Co on Fe/Cu(100)

A spin reorientation phase transformation can occur either by a continuous process, such as spin canting, or by an abrupt spin rotation. We investigate the spin reorientation of ultrathin Fe/Cu(100) films induced by Co capping layers using the magneto-optical Kerr effect. The spin axis reorients from the perpendicular to the in-plane direction when the amount of Co exceeds some critical value. Experimental evidence indicates that this transformation involves the formation of multidomains. In the transition thickness regime, we observed that the perpendicular and the in-plane remanent magnetization are complementary, and attribute this to the presence of an inhomogeneous anisotropy field.