Analysis of metal-in-gap heads

This paper describes some anomalous effects in the recording and playback performance of heads with thin metal layers on one or both gap surfaces. The most apparent effect, bumps in the output spectrum while reading with this metal-in-gap head, is discussed in detail. Under normal recording conditions no bumps are observed when another head is used for playback. The magnetic behaviour of the interface between metal layer and head-core material can be characterized with the expressions derived in the paper. Analogously the magnetic gap-length of very small gaps (even below 200Å) can be determined accurately by the aid of the derived expressions, when a larger gap is incorporated in the same head for that purpose.