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MR Ratio Enhancement by NOL Current-Confined-Path Structures in CPP Spin Valves

2004; IEEE Magnetics Society; Volume: 40; Issue: 4 Linguagem: Inglês

10.1109/tmag.2004.829185

1941-0069

Hideaki Fukuzawa, Hiromi Yuasa, S. Hashimoto, K. Koi, M. Iwasaki, M. Takagishi, Y. Tanaka, M. Sahashi,

Copper Interconnects and Reliability

We have compared the magnetoresistance (MR) performance of current-confined-path (CCP) current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin valve films with a nano-oxide-layer (NOL), made between natural oxidation (NO) and ion-assisted oxidation (IAO). For the NO, an MR ratio was only 1.5% at an RA of 370 m/spl Omega//spl mu/m/sup 2/, whereas for the IAO, an MR ratio was greatly increased to 5.4% at an RA of 500 m/spl Omega//spl mu/m/sup 2/. Fitted data by the Valet-Fert model showing larger MR enhancement effect by the IAO is explained by the improvement of the metal-purity of the Cu inside the CCP structure. By further improvement of metal-purity of the Cu, a large MR ratio of more than 30% can be expected at a small RA of 300 m/spl Omega//spl mu/m/sup 2/. The CCP-CPP spin valve film is a promising candidate for realizing high-density recording heads for 200 to 400-Gbpsi recording.