Beta (β) tungsten thin films: Structure, electron transport, and giant spin Hall effect
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- Qiang Hao
- Brown University Department of Physics, , Providence, Rhode Island 02912, USA
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- Wenzhe Chen
- Brown University Department of Physics, , Providence, Rhode Island 02912, USA
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- Gang Xiao
- Brown University Department of Physics, , Providence, Rhode Island 02912, USA
書誌事項
- 公開日
- 2015-05-04
- DOI
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- 10.1063/1.4919867
- 公開者
- AIP Publishing
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説明
<jats:p>We use a simple magnetron sputtering process to fabricate beta (β) tungsten thin films, which are capable of generating giant spin Hall effect. As-deposited thin films are always in the metastable β-W phase from 3.0 to 26.7 nm. The β-W phase remains intact below a critical thickness of 22.1 nm even after magnetic thermal annealing at 280 °C, which is required to induce perpendicular magnetic anisotropy (PMA) in a layered structure of β-W/Co40Fe40B20/MgO. Intensive annealing transforms the thicker films (>22.1 nm) into the stable α-W phase. We analyze the structure and grain size of both β- and α-W thin films. Electron transport in terms of resistivity and normal Hall effect is studied over a broad temperature range of 10 K to at least 300 K on all samples. Very low switching current densities are achieved in β-W/Co40Fe40B20/MgO with PMA. These basic properties reveal useful behaviors in β-W thin films, making them technologically promising for spintronic magnetic random access memories and spin-logic devices.</jats:p>
収録刊行物
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- Applied Physics Letters
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Applied Physics Letters 106 (18), 182403-, 2015-05-04
AIP Publishing
