Alloy Synthesis by Atomic Layer Laminations for Read Sensor Applications

Abstract

A novel method has been developed for synthesis of multi-element alloys by planetary magnetron sputter deposition techniques. The alloy is formed by alternating depositions of uniform ultra-thin component layers at a fraction of a mono-atomic layer, or atomic layer lamination. A minimal layer thickness of down to 0.1Å can be obtained such that the components can be mixed at atomic level forming a homogeneous alloy.

A typical example is demonstrated here for the synthesis of Co_xFe_1−x alloys by alternating depositions of Co and Fe layers from pure element targets. The compositional dependence of the laminates basically reconstructs the well-known Slater-Pauling curve of the bulk Co_xFe_1−x alloys. The laminates exhibit a clear structural transition at Co compositions between 60 and 80 % from fcc phase to bcc phase, characteristic of bulk Co_xFe_1−x alloys. The novel atomic layer lamination has been successfully applied to the composition optimization of CoFe pinned layer with a best pinning strength at Co₇₀Fe₃₀ for exchange biased spin-valve films.