Angular rotation of magnetic hysteresis of ion-irradiated ferromagnetic thin films

The magnetization direction of a cobalt-platinum film has been manipulated by magnetic-field-assisted ion-beam mixing. A uniaxial easy magnetization axis is induced along the oscillation direction of the incident beam of 80 keV Ar+ ions. The easy axis was then rotated by 60degrees, when the same ion irradiation process was carried out in the presence of an external magnetic field. Magnetic force microscopy measurements show that line shaped domain structures are created with their long axis along the induced magnetization directions. It is proposed that the creation of adjacent regions with orthogonal magnetization can play a crucial role in stabilizing the magnetostatic dipolar interaction between adjacent bits of magnetic data storage devices. (C) 2002 American Institute of Physics.