Which spin valve for next giant magnetoresistance head generation? (invited)

Abstract

To maintain a challenging 100%/year growth rate of the areal density, new spin valve (SV) structures have recently emerged. This work reviews the transport properties of hybrid free, synthetic, and specular SV at film level and discusses their potential for read head application. High sensitivity can be achieved using hybrid free and synthetic free SV due to their small net magnetic moment, but the longitudinal biasing of synthetic free SV is a critical issue. Good thermal stability was obtained in both synthetic pinned and specular SV due to high effective exchange field or good protection from interdiffusion. Moreover, specular SV also shows large output. With structure having different benefits, the next generation of SV head should be a combination to optimize all properties. Nevertheless, it raises many technological issues, related to the processing of very thin layers, which should be solved to meet the requirements of reproducibility and high yield from mass production.