Electrostatic popping in AMR and GMR heads

摘要

Dielectric breakdown of insulating layers between the MRE (magneto resistive element) and the conducting shields generates another type of base line shift or popping noise in MR heads. Pulse shapes are similar to those of thermal asperities, but they can be bipolar and can occur without a disk. Measurements illustrate the difficulties of characterizing these pulses. A physical model is proposed to explain the behavior, and a simple SPICE simulation shows similar pulse behavior.