A NEW TECHNIQUE OF NOISE-REDUCTION FOR LARGE ASPECT MAGNETORESISTORS

A large aspect (width to thickness ratio) magnetoresistive sensor oper ated with an alternating transverse biasing is characterized by high s ensitivity and reduced temperature drift. However, it has little demag netizing anisotropy to maintain a single domain state so noisy behavio r often results. A constant longitudinal field can be used to reduce t his noise but at the expense of reduced sensitivity. A new unipolar a. c. longitudinal blasing technique is presented which allows the full s ensitivity to be achieved whilst significantly reducing magnetic noise and hysteresis.