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At IEE RAS, from the middle of the 1960s, the investigations of pulsed electric arcs in hydrogen, nitrogen, argon, etc., at high initial density are carried out. From this time, many pulsed plasmatrons (PPs), electrodischarge light-gas launchers (EDL), combined systems, unique diagnostic PP operating at hydrogen at initial pressure up to 150 MPa, and experimental facilities had been developed. The highest energy in the world of 10 MJ supplied from the shock generator into the discharge chamber of PP was input. Many experimental data on processes in the EDL and PP were obtained. The bodies of 0.2 g to ~9 km/s, 12 g to ~6 km/s, and 300 g to ~2 km/s were launched. Index Terms--Electric arc, high current, hydrogen, launching, pulsed discharge.

Through an electrostatic discharge (ESD) damage case study of giant magnetoresistive (GMR) head in shunting process of head gimbal assemblies (HGA), this paper unveils that GMR heads would be damaged by a combination of field-induced voltage on HGA and surrounding trigger event. This investigation further demonstrates that the ESD protection technique, which derives from metal-to-metal contact to GMR terminals and thus focuses on eliminating metal-to-metal contact to GMR terminals, is not sufficient to prevent ESD. The electromagnetic interference caused by nearby trigger event needs to be noted also in the ESD control. Index Terms--Electromagnetic interference (EMI), electrostatic discharge (ESD), GMR, HGA.

The electrical breakdown behavior and damage mechanisms for a recording head flying over a charged hard disk with and without an asperity is studied. It was found that the breakdown voltage flying over a 30-nm-high asperity was as low as 1.4 V, a 50% reduction compared with a smooth disk without the asperity. Also, the read sensor was easily damaged physically and magnetically when breakdown occurred while flying over the asperity. It is concluded that the inclusion of asperities in electrical breakdown testing is critically important in determining the lowest breakdown voltage and assessing the likelihood of damage to the sensor. Index Terms--Asperity, electrical breakdown, electrostatic discharge (ESD), head-disk interface.

We report on the investigation of electrostatic discharge (ESD) sensitivity of current perpendicular to plane (CPP) magnetic tunnel junction (MTJ) heads used in hard disk drives (HDD). Our results show that MTJs have different degradation characteristics and mechanisms from current in-plane (CIP) giant magnetoresistive (GMR) heads when exposed to cumulative ESD current transients. Both MTJ and GMR heads show gradual amplitude degradation as a result of increasing ESD levels, but MTJs are more robust than GMR heads in terms of sensor stack magnetic stability, such as polarity flip. Large ESD voltages could change stability state of the MTJ heads, which shows up as random telegraph noise associated with transfer curve magnetic distortions in low-frequency regime and noise spikes several times above baseline noise in high-frequency regime. This MTJ instability is likely a result of defects in the multilayer reader magnetics and disturbances, as well as degradation of tunnel oxide barrier. Index Terms--Electrostatics, magnetic heads, noise, tunnel junctions.