Control of asymmetry of spin valve heads based on micromagnetic analysis

Relationship between the asymmetry of spin-valve heads and various parameters is revealed by systematical investigations of a micromagnetic analysis. We design spin-valve heads with a good asymmetry by canting the pinned layer. However, for spin-valve heads for high density recording over 10 Gb/in², a poor asymmetry caused by the degeneration of the magnetization direction of the free layer becomes a serious problem. To solve this problem, we introduce a bias compensation layer (BCL) to the spin-valve structure. We prove that BCL is very effective in controlling the asymmetry