Longitudinally biased magnetoresistive sensor having a concave shaped active region to reduce Barkhausen noise by achieving a substantially single magnetic domain state

摘要

A magnetoresistive ("MR") sensor (100) constructed with a concave shaped edge (102) in order to provide an effective longitudinal bias field in the center of the active MR element sufficient to obviate multi-domain states and concomitant Barkhausen noise. Utilizing the concave shape proposed herein, the "stripe height" of the element is at a minimum (SHMIN) in the center of the active region (ARL) and increases toward the off-track boundary. In a preferred embodiment, a substantially constant effective longitudinal bias field may be obtained throughout the active MR element if the stripe height increases as an exponential function of the square of the off-track distance. The principles of the present invention are likewise applicable to use in spin valve ("SV") and other giant magnetoresistive ("GMR") sensors.