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Magnetoresistance Characteristics of Magnetic Tunnel Junctions Consisting of Amorphous CoNbZr Alloys for Under and Capping Layers |
Journal of Magnetics, Volume 9, Number 1, 31 Mar 2004, Pages 13-16 |
Byong Sun Chun(Division of Materials Science and Engineering, Korea University), Seong-Rae Lee(Division of Materials Science and Engineering, Korea University), Young Keun Kim* (Division of Materials Science and Engineering, Korea University) |
Abstract |
Magnetic tunnel junctions (MTJs) comprising amorphous CoNbZr layers have been investigated. Co85.5Nb8Zr6.5 (in at. %) layers were employed to substitute the traditionally used Ta layers with an emphasis given on under-standing underlayer effect. The typical junction structure was SiO2/CoNbZr or Ta 2/CoFe 8/IrMn 7.5/CoFe 3/Al 1.6 + oxidation/CoFe 3/CoNbZr or Ta 2 (nm). For both as-deposited state and after annealing, the CoNbZr-underlayered structure showed superior surface smoothness up to the tunnel barrier than Ta-underlayerd one (rms roughness of 0.16 vs. 0.34 nm). CoNbZr-based MTJs was proven beneficial for increasing thermal stability and increasing Vh (the bias voltage where MR ratio becomes half) characteristics than Ta-based MTJs. This is because the CoNbZr-based junctions offer smoother interface structure than the Ta-based one. |
Keywords: Magnetic Tunnel Junction; Thermal Stability; Bias Voltage Dependence; CoNbZr; Surface Roughness |
DOI: |
Full Text: PDF |
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