Effects of submonolayer Mg on CoFe-MgO-CoFe magnetic tunnel junctions

Journal Article · Wed Oct 01 04:00:00 EDT 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2991439· OSTI ID:21182670

Huang, J C. A.; Hsu, C Y ^[1]; Chen, W H; Lee, Y H ^[1]; Chen, S F; Liu, C P ^[2]; Yonhua, Tzeng ^[3]

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1. Physics Department, National Cheng Kung University, Tainan, Taiwan 701 (China)
2. Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China)
3. Institute of Innovations and Advanced Studies (ILAS), National Cheng Kung University, Tainan, Taiwan 701 (China)

CoFe-MgO-CoFe magnetic tunnel junctions (MTJs) were fabricated by means of ion beam sputtering of MgO as well as subsequent thin films on CoFe. We demonstrated that when a submonolayer of Mg was deposited on the CoFe layer prior to the deposition of MgO, profound improvement in the performance of the CoFe-Mg-MgO-CoFe MTJ was achieved compared to that without the Mg layer. ac impedance measurement indicated that the interfacial Mg layer resulted in fivefold increase in the magnetoresistance ratio from 0.76% for MTJs without it to 4% for that with it. Complex-capacitance (CC) spectra of MTJs showed that the contribution in the relaxation frequency by textured MgO increased. This indicated that the submonolayer Mg improved the texture of the subsequently deposited MgO. Bias-dependent complex-impedance (CI) spectra reveal that interfacial defects were also suppressed due to the submonolayer of Mg. Results obtained from x-ray reflectivity and transmission electronic microscopy were also consistent with those of CI and CC.

• OSTI ID: 21182670
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 104; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CAPACITANCE
COBALT COMPOUNDS
DEPOSITION
ELECTRIC IMPEDANCE
ION BEAMS
IRON COMPOUNDS
LAYERS
MAGNESIUM OXIDES
MAGNETORESISTANCE
REFLECTIVITY
SPUTTERING
SUPERCONDUCTING JUNCTIONS
TEXTURE
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT
X RADIATION