Title :
Effect of Interface Roughness on Magnetoresistance and Magnetization Switching in Double-Barrier Magnetic Tunnel Junction
Author :
Hwang, J.Y. ; Lee, S.Y. ; Lee, N.I. ; Yim, H.I. ; Kim, M.Y. ; Lee, W.C. ; Rhee, J.R. ; Chun, B.S. ; Kim, T.W. ; Kim, Y.W. ; Lee, S.S. ; Hwang, D.G. ; Ri, E.J.
Author_Institution :
Dept. of Phys., Sookmyung Women´´s Univ., Seoul
fDate :
6/1/2009 12:00:00 AM
Abstract :
The three kinds of double-barrier magnetic tunnel junction (DMTJ) with or without amorphous ferromagnetic Co70.5Fe4.5Si15B10 (in at. %) free-layer were investigated to understand the effect of the free-layer on the bias voltage dependence of tunneling magnetoresistance (TMR) ratio. The DMTJ structure consisted of Ta 45/Ru 9.5/IrMn 10/CoFe 7/AlOx/free-layer 7/AlOx/CoFe 7/IrMn 10/Ru 60 (thickness in nm). Various free layers, such as CoFe 7, CoFeSiB 7, and CoFe 1.5/CoFeSiB 4/CoFe 1.5 were prepared and compared. The roughness values of the interface between free-layer and tunnel barrier were confirmed by using the techniques of X-ray reflectivity and transmission electron microscopy. As a result, the amorphous free-layer made the interface roughness of DMTJ smoother, reducing the interlayer coupling field and suppressing the bias voltage dependence of TMR ratio at a given voltage.
Keywords :
X-ray reflection; aluminium compounds; amorphous magnetic materials; boron alloys; cobalt alloys; ferromagnetic materials; interface roughness; iridium alloys; iron alloys; magnetic multilayers; magnetic switching; magnetisation; manganese alloys; ruthenium; silicon alloys; tantalum; transmission electron microscopy; tunnelling magnetoresistance; CoFeSiB; Ta-Ru-IrMn-CoFe-AlOx-Co70.5Fe4.5Si15B10-AlOx-CoFe-IrMn-Ru; X-ray reflectivity; amorphous ferromagnetic free-layer; bias voltage dependence; double-barrier magnetic tunnel junction; interface roughness; interlayer coupling field; magnetization switching; transmission electron microscopy; tunneling magnetoresistance; Amorphous ferromagnetic; CoFeSiB; bias voltage dependence; magnetic tunnel junction;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2009.2018586
