Tribocharging and electrical breakdown at the magnetic recording head-disk interface

In order to quantify the risk of ESD damage during head-disk contact, tribocharging of a floating GMR reader flying over a grounded aluminum and bare glass disk was studied. In addition, the electrical breakdown voltage between a grounded GMR reader and a charged disk was measured. Severe damage resulted during spin up using the bare glass disk. Tribocharging of the GMR sensor due to head-disk interaction was only 200 mV, less than the ~1.6V to 20V required to cause head-disk breakdown. It is concluded that head-to-disk breakdown is possible if the voltage of one or more of the conductors at the head-disk interface is not controlled.