Recording at Large Write Currents on Obliquely Evaporated Medium and Application to a Multilevel Recording Scheme

We have studied the recording process of an obliquely evaporated Co-CoO medium. The experimental readback waveforms and the spin-SEM images of the recorded magnetization reveal an interesting magnetization process upon increasing the write current in one of the two recording directions. With larger write currents, isolated readback pulses drastically change their shape and the remanent magnetization of the written domains decreases. We qualitatively reproduce this behavior using simple write models that include the three-dimensional (3-D) granular nature of the medium and a distribution of anisotropy axes for the evaporated Co grains. Based on these results, we propose a recording scheme in which a patterned multilevel tilted recording medium is used advantageously for 3-D magnetic recording.