Seed layer for improving pinning field spin valve sensor

摘要

A seed layer is provided for a pinning layer which increases the pinning field HPIN between a pinning layer and a pinned layer of a spin valve sensor. In an example the seed layer structure included a first seed layer of cobalt iron boron (CoFeB), a second seed layer of nickel manganese oxide (NiMnO) and a third seed layer of aluminum oxide (Al2O3) with the first seed layer interfacing the pinning layer and the second seed layer being located between the first and third seed layers. A pinning field between the pinning and pinned layers was 600 Oe and the magnetoresistive coefficient of the spin valve sensor was 8.8%. The pinned layer can be a single pinned layer or an antiparallel (AP) pinned layer structure. If the pinned layer structure is a single pinned layer the cobalt iron boron (CoFeB) first seed layer provides a second significant function of at least partially counterbalancing the demagnetizing field from the pinned layer.