Co/Ni multilayers with perpendicular magnetic anisotropy : Kerr effect and thermomagnetic writing

Perpendicular magnetic anisotropy has recently been predicted and confirmed for a Co1/Ni2 multilayer [G. H. O. Daalderop, P. J. Kelly, and F. J. A. den Broeder, Phys. Rev. Lett. 68, 682 (1992)]. This letter reports on some magneto-optical properties of this new multilayer. Its polar Kerr effect appeared to be considerably larger than for a Co1/Pd2 multilayer and comparable to a Co1/Pt2 multilayer. For certain vapor deposition conditions, the perpendicular magneto-optic hysteresis loop of a 120 Å Co1/Ni2 layer showed 100% remanence with a coercivity as high as 140 kA/m. Thermomagnetic writing was possible despite the high Curie temperature.