Perpendicular Anisotropy of Evaporated Magnetic Iron-Nickel and Cobalt-Nickel Thin Films

The perpendicular anisotropy, Which has its easy axis perpendicular to the film surface and thus is the origin of the stripe domains, was measured for nickel, nickel-iron, and nickel-cobalt films directly by means of a wide-range sensitivity torque magnetometer. It was found that the perpendicular anisotropy constant, K ⊥ , is composed of the shape anisotropy, magnetostrictive anisotropy and the anomalous part. A large anomalous part was found to appear by the evaporation at the substrate temperature ranging from -120°C to 100°C, in a relatively bad vacuum. The origin of this anomalous part seems to be related to elongated non-magnetic inclusions or voids formed during evaporation