Experimental Study of Perpendicular Write Heads at Data Rates Beyond 2 Gb/s

A modified contact tester utilizing RF probes is used to test perpendicular write heads at slider level with frequencies up to 3.3 GHz. The setup enables demonstration of the recording dynamic effects at extremely high frequency. A study using single pulse writing at deep sub-nanosecond pulse widths has been performed as a function of write current amplitude. The sub-nanosecond writes show clear current polarity dependence. AC erasure performed at different frequencies and current amplitudes indicates possible head magnetization dynamics that may cause the ac field degradation and disappearance at very high current switching frequencies. For some head, the ac erasure at certain driving frequencies is able to lock the head magnetization into remanence state instead of demagnetizing it