Title :
Effects of interface oxidization in ferromagnetic tunnel junctions
Author :
Sato, Masashige ; Kikuchi, Hideyuki ; Kobayashi, Kazuo
Author_Institution :
Fujitsu Labs. Ltd., Atsugi, Japan
fDate :
9/1/1999 12:00:00 AM
Abstract :
We fabricated Ni-Fe/Co/Al-AlO/Co/Ni-Fe/Fe-Mn/Ni-Fe ferromagnetic tunnel junctions in which the bottom Co surface is exposed or not to air. While the MR ratio increased by annealing for the sample in which bottom Co surface was exposed to air, it decreased for the sample in which bottom Co surface was not exposed to air. This suggests that a slightly oxidized layer at the bottom Co/Al interface acts as a diffusion prevention layer. Moreover, the voltage-resistance dependence became asymmetric following annealing of the sample with a non oxidized Co surface and the bias dependence of MR ratio was improved
Keywords :
alumina; aluminium; annealing; cobalt; diffusion barriers; ferromagnetic materials; giant magnetoresistance; interface structure; iron alloys; magnetic multilayers; manganese alloys; nickel alloys; oxidation; tunnelling; MR ratio; NiFe-Co-Al-Al2O3-Co-NiFe-NiMn-NiFe; NiFe/Co/Al-AlO/Co/NiFe/FeMn/NiFe ferromagnetic tunnel junctions; annealing; bias dependence; bottom Co surface; bottom Co/Al interface; diffusion prevention layer; ferromagnetic tunnel junctions; interface oxidization; slightly oxidized layer; voltage-resistance dependence; Annealing; Laboratories; Lithography; Magnetic field measurement; Magnetic films; Magnetic separation; Sputtering; Surface fitting; Temperature; Voltage;
Journal_Title :
Magnetics, IEEE Transactions on
