Giant magnetoresistance in Ni-Fe/Co/Al-AlO(x)/Co/Ni-Fe/Fe-Mn ferromagnetic tunnel junctions

To develop candidate magnetic sensors for the future generation of magnetic read-heads, we have fabricated Ni-Fe/Co/Al-AlO(x)/Co /Ni-Fe/Fe-Mn/Ni-Fe ferromagnetic tunnel junctions with oxidized Al barriers. To form the barrier layer, the Al was oxidized in air or in oxygen plasma. These junctions sho...

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Bibliographic Details
Published in:Fujitsu scientific & technical journal 1998-12, Vol.34 (2), p.204-211
Main Authors: Sato, Masashige, Kikuchi, Hideyuki, Kobayashi, Kazuo
Format: Article
Language:English
Online Access:Get full text
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Summary:To develop candidate magnetic sensors for the future generation of magnetic read-heads, we have fabricated Ni-Fe/Co/Al-AlO(x)/Co /Ni-Fe/Fe-Mn/Ni-Fe ferromagnetic tunnel junctions with oxidized Al barriers. To form the barrier layer, the Al was oxidized in air or in oxygen plasma. These junctions showed changes in tunnel resistance (magnetoresistance ratio) of 10-15 percent upon application of a magnetic field. Some of the junctions exhibited good thermal stability above 300 C, and the magnetoresistance (MR) ratios were increased by annealing. The largest MR ratio after annealing at 300 C for one hour was 24 percent, which is much larger than that of spin-valve films. The junctions with naturally oxidized barriers and plasma-oxidized barriers had almost the same properties, but the plasma-oxidization process is much faster. Current research indicates that ferromagnetic tunnel junctions have good potential for use in magnetic read heads. (Author)
ISSN:0016-2523