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Pd Layer Thickness Dependence of Tunnel Magnetoresistance Properties in CoFeB/MgO-Based Magnetic Tunnel Junctions with Perpendicular Anisotropy CoFe/Pd Multilayers
Kotaro Mizunuma1,
Michihiko Yamanouchi2,
Shoji Ikeda1,2,
Hideo Sato2,
Hiroyuki Yamamoto3,
Hua-Dong Gan2,
Katsuya Miura1,2,3,
Jun Hayakawa3,
Fumihiro Matsukura1,2, and
Hideo Ohno1,2
1Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
2Center for Spintronics Integrated Systems, Tohoku University, Sendai 980-8577, Japan
3Advanced Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo 185-8601, Japan
(Received December 15, 2010; accepted January 18, 2011; published online February 4, 2011)
The authors investigated tunnel magnetoresistance (TMR) properties in [CoFe/Pd]-multilayer/CoFeB/MgO/CoFeB/[Pd/CoFe]-multilayer magnetic tunnel junctions (MTJs) having two different Pd layer thicknesses. By reducing the Pd layer thickness from 1.2 to 0.2 nm, the TMR ratio was enhanced from 7 to 101% at the annealing temperature (Ta) of 300 °C. The thin Pd layers resulted in high residual B concentration in the CoFeB layer after high-Ta annealing and in the suppression of crystallization of the CoFeB layer from the fcc(111)-Pd layer side.
©2011 The Japan Society of Applied Physics
URL:
http://apex.jsap.jp/link?APEX/4/023002/
DOI: 10.1143/APEX.4.023002
PACS: 85.75.Dd, 75.30.Gw, 75.50.Bb, 75.47.Lx
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