Effects of mixed gases on characteristics of specular spin-valves containing oxide layers

Abstract

Specular spin valves containing oxide layers (OXLs), structured as substrate/seed/AF/P1/OXL/P2/Cu/ F/OXL, have been fabricated. The OXLs were formed by natural oxidation in different ambient atmospheres of pure oxygen, of oxygen/nitrogen, and of oxygen/argon gas mixtures. The fabrication conditions were optimized to enhance the magnetoresistance (MR) ratio, to suppress the interlayer coupling fields (Hf) between the free and pinned layers, to suppress the high interface density of the OXL, to ease the control of the OXL thickness and to form a smooth OXL/P2 interface for promoting specular electron scattering. The characteristics of our specular spin valves are as follows: the MR ratio of 14.1%, the exchange bias field of 44–45 mT and Hf weaker than 1.0 mT. The optimal conditions for oxidation time, total oxidation pressure and the annealing temperature were found to be of 300 s, 0.13 Pa (oxygen/ argon = 8/2), and 250 °C, respectively. The results suggest that specular spin-valves containing OXLs satisfy the requirements of read head performances in high density (100 Gbits/in2) recording devices. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)