LONG-TIME ANNEALING AND ACTIVATION ENERGY OF THE INTERDIFFUSION AT AlOx/Co-Fe/Ir-Mn INTERFACES

Dual-spin-valve-type double magnetic tunnel junctions (double MTJs) of sputtered Ir-Mn/CoFe/AlOx/CoFeNi/AlOx/CoFe/Ir-Mn were fabricated using photolithography and ion-beam milling. The double MTJs were subjected to long-time annealing at various temperatures (185-400 C) in order to investigate the t...

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Published in:Jpn.J.Appl.Phys ,Part 1. Vol. 43, no. 5A, pp. 2484-2488. 2004 Part 1. Vol. 43, no. 5A, pp. 2484-2488. 2004, 2004-01, Vol.43 (5A), p.2484-2488
Main Authors: Saito, Y, Amano, M, Nishiyama, K, Asao, Y, Tsuchida, K, Yoda, H
Format: Article
Language:English
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Summary:Dual-spin-valve-type double magnetic tunnel junctions (double MTJs) of sputtered Ir-Mn/CoFe/AlOx/CoFeNi/AlOx/CoFe/Ir-Mn were fabricated using photolithography and ion-beam milling. The double MTJs were subjected to long-time annealing at various temperatures (185-400 C) in order to investigate the thermal stability due to the interdiffusion. Magnetoresistance (MR) ratio and resistance were measured at room temperature before and after annealing. The thermal changes of MR ratio are well-explained by considering three phenomena with effective activation energies of 2.6 eV, 0.26 eV, and 1.9 eV. These values are in good agreement with the activation energies of the interdiffusion based on the vacancy mechanism. The three phenomena with the effective activation energies are well-explained by considering the interdiffusion and redistribution of O and Mn at the AlOx/Co-Fe/Ir-Mn interfaces. Based on the effective activation energies, it is evaluated that there would be no significant changes in the MR ratio in MTJs with CoFe(3 nm)/IrMn pinned layers for a period of more than 10 years at 160 C. 14 refs.
ISSN:0021-4922
DOI:10.1143/JJAP.43.2484