Effect of natural oxidation conditions on low resistance spin tunnel junctions
Effect of natural oxidation conditions on low resistance spin tunnel junctions
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自然氧化条件对低电阻自旋隧道结的影响
DOI：
10.1063/1.1447209
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发表时间：
2002
影响因子：
3.2
通讯作者：
J. Soares
中科院分区：
文献类型：
--
作者：
Zongzhi Zhang;P. Freitas;A. R. Ramos;N. Barradas;J. Soares
用原位自然氧化法制备了7（或8）厚的Al膜，制备了具有AlOx势垒的自旋相关隧道结。在预退火的、离子束平滑的、600 A厚的Al底部电极的顶部沉积结。在氧压为10和100 Torr的条件下，氧化时间从10 min变化到10 h时，顶钉扎结的电阻从31 Ω μm2变化到406 Ω μm2，隧穿磁电阻（TMR）从8.5%变化到19.6%。对于底部钉扎结，氧气压力从0.5到100 Torr变化，氧化时间从5 min到2 h。在较低的氧化压力（0.5Torr）下，当TMR为14%~ 17%时，获得了低至10-12 Ω μ m ~ 2的底部钉扎结电阻。卢瑟福背散射分析（RBS）表明O/Al比为1.29±0.34，表明在较低压力和短时间下氧化的结的Al的不完全氧化。结氧化在较高的压力（1000托）c.
Spin dependent tunnel junctions with AlOx barrier were fabricated by in situ natural oxidation of a 7 A (or 8 A) thick Al film. Junctions were deposited on top of preannealed, ion-beam smoothed, 600 A thick Al bottom electrodes. By changing the oxidation time from 10 min to 10 h with the oxygen pressure of 10 and 100 Torr, the top-pinned junctions have resistances varying from 31 to 406 Ω μm2 and the tunneling magnetoresistance (TMR) varies from 8.5% to 19.6% for the as deposited state. For the bottom-pinned junctions, the oxygen pressure was varied from 0.5 to 100 Torr, and oxidation time ranged from 5 min to 2 h. Bottom-pinned junction resistances as low as 10–12 Ω μm2 were obtained with TMR ranging from 14% to 17% for the junctions oxidized at the lower pressure (0.5 Torr). Rutherford backscattering analysis (RBS) indicates an O/Al ratio of 1.29±0.34 denoting incomplete oxidation of the Al for junctions oxidized at the lower pressures and short times. Junctions oxidized at higher pressures (⩾10 Torr) c...