Unshielded MR elements with patterned exchange-biasing

The concept of patterned longitudinal biasing as a means to suppress Barkhausen noise in narrow-track MR (magnetoresistive) elements without under permeability degradation of the read region is discussed. This scheme also renders the performance of the read region relatively insensitive to the exact magnitude of the externally applied longitudinal bias, as long as this bias is large enough to ensure good longitudinal alignment of magnetization at the tail regions. This concept was demonstrated with Permalloy MR elements using patterned exchange biasing. Results show that these elements do indeed exhibit quiet and stable responses, but without the severe sensitivity reduction which is characteristic of MR elements under normal strong uniform longitudinal biasing