Pt-Doped Al2O3 as Dissipative Gap-Material in Tape Heads

A giant magnetoresistive (GMR) head in tape recording systems is affected by the electrostatic discharge (ESD) between the sensor and magnetic shields. Pt-doped Al₂O₃ was developed as a dissipative gap-material to reduce the ESD current. Pt chips were sputtered on an alumina target to vary the film resistance. The decay time of a charged plate on Pt-doped Al₂O₃ was measured for various film thicknesses. The I-V characteristics indicated that as the applied voltage increased, the Pt-doped Al₂O₃ film increased the current gradually, whereas the Al₂O₃ film increased the current rapidly over the breakdown voltage. An ESD pulse test showed that the Pt-doped Al₂O₃ film suppressed the peak current approximately 1/40 compared to the Al₂O₃ film. The microstructure of the Pt-doped Al₂O₃ gap in a tape head was characterize by TEM and its Pt distribution by EDX mapping.