Suppression of Barkhausen noise in an MR head

Abstract

It is shown by the Bitter technique that magnetic domain walls nucleate at the ends of a long magnetoresistive (MR) element and propagate into the active central region as the transverse field is successively increased. A new technique utilizing current loops only at the ends of the element is used to apply longitudinal bias to suppress Barkhausen noise. Suppression of Barkhausen noise is also accomplished by minimizing longitudinal demagnetizing field using a high aspect ratio MR element, as well as minimization of the transverse demagnetizing field by overlapping two pieces of a yoke with the transverse edges of the MR element. These techniques are used to fabricate a Barkhausen noise-free yoke-type MR head.