MR ratio enhancement by NOL current-confined-path structures in CPP spin valves

• Published in: IEEE transactions on magnetics Vol. 40; no. 4; pp. 2236 - 2238
• Main Authors: Fukuzawa, H., Yuasa, H., Hashimoto, S., Koi, K., Iwasaki, H., Takagishi, M., Tanaka, Y., Sahashi, M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.07.2004; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Giant magnetoresistance; Lamination; Lithography; Magnetic heads; Magnetic properties and materials; Magnetism; Oxidation; Physics; Scattering; Space technology; Spin valves; Testing; Tunneling magnetoresistance; CPP-GMR; current-confined-path; Magnetic materials; oxides; spin valves
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2004.829185

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.