(Invited) Linear Magnetic Tape Heads and Contact Recording

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.