Contact-dependent reliability of spin valve heads

Contact-dependent failure modes were observed in spin valve sensors in nomi nal current density range of 2 - 5 x 10(7) A/cm(2) at 70 degrees C ambient. At high bias condition, continually decreased quasistatic test (QST) trans fer curve amplitude with negligible resistance change was observed in senso rs abutted with Ta contact, In contrast, steady resistance rise with relati vely unchanged amplitude was seen in Ta/Au/Ta-contact device prior to catas trophic burnout. Void formation is apparent in the Au layer of the burnout device, Locations of the voids show bias polarity dependency, suggesting an electromigration mechanism in the Au layer.