Switching noise in yoke magneto-resistive heads

Magnetic noise generated in yoke magneto-resistive (MR) heads was investigated in detail. The so-called Barkhausen noise, which originates from magnetic domain activities in an MR element, is noticeably suppressed by placing hard magnetic layers on the wing regions of the element. Even in yoke MR heads, in which the MR elements are stabilized by this method, we observed a noise similar to the Barkhausen noise. From the nature of the noise generated, it was inferred that this noise was created by magnetic switching in the MR element. Conditions of switching noise generation were analyzed by the Stoner-Wohlfarth model. This analysis revealed that the switching noise can be suppressed by rotating the average easy axis of the MR element with respect to the longitudinal direction. This expectation was definitely confirmed through fabrication of the yoke MR heads.<
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