(Invited) Linear Magnetic Tape Heads and Contact Recording

Abstract

Linear tape recording heads, introduced in 1984, originally were cylindrical ferrite structures having shunt-biased magnetoresistive sensors. In 2000, heads transitioned to flat-lapped, ceramic wafers and anisotropic magnetoresistive (AMR) sensors fabricated in hard disk drive (HDD) facilities. In 2008, heads transitioned to giant magnetoresistive (GMR) sensors. Engineering tape heads has meant dealing with problems related to the head-media interface. Examples include sub-nanosecond pulses in sensors having metal shields (ca. 1994), signal losses and telegraph noise caused by parasitic electrical connections and spacing due to deposits that form at low relative humidity. Wear management, especially with 'green' media, and stick-slip effects are on-going challenges. A strategy was created for protecting GMR tape heads, leading to the discovery of polycrystalline Al2O3 films.

Deposition Technologies

“…Ever since thin-film recording heads for disc drives were commercialized in 1979 by IBM, magnetic and conductive elements for these devices were fabricated by electrochemical deposition [153]. Similar technologies were used for tape heads [163]. Quite a few applications are to be found in the field of microactuation, including magnetic microvalves and MEMS brushless DC micromotors [164].…”