Amplitude and asymmetry study using magnetoresistive sensitivity mapping (MSM) on manufacturing ESD failures and ESD simulation experiments

Magnetoresistive Sensitivity Mapping (MSM) is used to investigate hard and soft electrostatic discharge (ESD) damage on anisotropic magnetoresistive (AMR) readers from manufacturing failures and simulation experiments. Unipolar MSM data is compared with sensor output voltage amplitudes which are measured using signals from magnetic transitions written on a high density magnetic tape. A bipolar MSM technique using two oppositely magnetized tips to measure the AMR sensitivity was applied to reveal sensor asymmetry. Multiple domains are observed on sensors exposed to soft ESD. Re-magnetization of the soft ESD damaged head showed the soft ESD damage is irreversible.