Effect of secondary gaps in near-saturated metal-in-gap video heads

Secondary gaps between the ferrite bulk and the Sendust (AlFeSi alloy) shim may occur in metal-in-gap (MIG) heads. Finite-element models are used to explore the effect that these gaps have on the read/write characteristics of single- and double-sided MIG heads. The presence of a secondary gap is shown to cause an additional peak in the writing field and oscillations in the magnitude of the response during replay. The field and response of a double-sided MIG head is affected more than those of the corresponding single-sided MIG head.