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Bias voltage dependence of magnetic tunnel junctions comprising amorphous ferromagnetic CoFeSiB layer with double barriers
Author(s) -
Yim H. I.,
Lee S. Y.,
Hwang J. Y.,
Rhee J. R.,
Chun B. S.,
Wang K. L.,
Kim Y. K.,
Kim T. W.,
Lee S. S.,
Hwang D. G.
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200723639
Subject(s) - materials science , ferromagnetism , amorphous solid , magnetoresistance , quantum tunnelling , condensed matter physics , tunnel magnetoresistance , biasing , crystallite , layer (electronics) , barrier layer , voltage , magnetic field , composite material , metallurgy , optoelectronics , electrical engineering , crystallography , chemistry , physics , engineering , quantum mechanics
Double‐barrier magnetic tunnel junctions (DMTJs) with and without an amorphous ferromagnetic material such as CoFeSiB 10, CoFe 5/CoFeSiB 5, and CoFe 10 (nm) were prepared and compared to investigate the bias voltage dependence of the tunneling magnetoresistance (TMR) ratio. Typical DMTJ structures were Ta 45/Ru 9.5/IrMn 10/CoFe 7/AlO x /free layer 10/AlO x /CoFe 7/IrMn 10/Ru 60 (in nanometers). The interlayer coupling field and the normalized TMR ratios at the applied voltages of +0.4 and –0.4 V of the amorphous CoFeSiB free‐layer DMTJ offer lower and higher values than that of the polycrystalline CoFe free‐layer DMTJ, respectively. An amorphous ferromagnetic CoFeSiB layer improves the interface roughness of the free layer/tunnel barrier and, as a result, the interlayer coupling field and bias voltage dependence of the TMR ratio are suppressed at a given voltage. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)