Title :
Tunnel Magnetoresistance Properties of Double MgO-Barrier Magnetic Tunnel Junctions With Different Free-Layer Alloy Compositions and Structures
Author :
Gan, Huadong ; Ikeda, Shoji ; Yamanouchi, Michihiko ; Miura, Katsuya ; Mizunuma, Kotaro ; Hayakawa, Jun ; Matsukura, Fumihiro ; Ohno, Hideo
Author_Institution :
Center for Spintronics Integrated Syst., Tohoku Univ., Sendai, Japan
fDate :
6/1/2011 12:00:00 AM
Abstract :
We investigated tunnel magnetoresistance (TMR) properties in double MgO-barrier magnetic tunnel junctions (DMTJs) with (Co25Fe75)100-xBx free-layers with x = 15, 20, and 25 (in at.%) sputtered at different power. The TMR ratio of DMTJs increased with sputtering power, which is ascribed to the B composition reduction in the CoFeB free-layer with increasing sputtering power. The x-ray diffraction measurement showed that crystallization into (001)-oriented texture of CoFeB film sandwiched between the two MgO-layers as well as an improvement of (001) orientation of top MgO-barrier are realized. The TMR ratio over 200% was obtained in DMTJs with a (Co25Fe75)85B15 free-layer sputtered at 0.88 and 1.77 W/cm2.
Keywords :
X-ray diffraction; boron alloys; cobalt alloys; crystallisation; iron alloys; magnesium compounds; magnetic multilayers; tunnelling magnetoresistance; (001)-oriented texture; (Co25Fe75)100-xBx free-layers; B composition reduction; CoFeB free-layer; MgO-(Co25Fe75)100-xBx-MgO; TMR ratio; X-ray diffraction; crystallization; double MgO-barrier magnetic tunnel junctions; free-layer alloy compositions; sputtering power; tunnel magnetoresistance properties; Annealing; Iron; Junctions; Magnetic tunneling; Sputtering; Tunneling magnetoresistance; MgO barrier; sputtering condition; tunnel magnetoresistance;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2010.2104137
