ESD sensitivity of GMR heads: effect of pulse length and number of events

GMR heads were subjected to electrical overstress using square current pulses of variable duration. The pulse length ranged from 4 ns to 80 ms. The number of events was varied as well between 1 and 10⁶ pulses. For each stress condition, the magnetic and physical failure thresholds were determined using quasistatic testing. We examined two different types of heads, designed for recording densities of 9 Gb/in² and 23 Gb/in². It is found that for long pulses (≳1 μs) the GMR sensors fail at almost constant power, whereas at very short times (<100 ns) the system becomes more and more adiabatic