Spin polarization and Gilbert damping of Co 2Fe(Ga xGe 1-x) Heusler alloys

B. S.D.Ch S. Varaprasad, A. Srinivasan, Y. K. Takahashi, M. Hayashi, A. Rajanikanth, K. Hono*

*この研究の対応する著者

研究成果: Article査読

75 被引用数 (Scopus)

抄録

The spin polarization (P) of ferromagnetic Heusler alloys, Co 2Fe(Ga xGe 1-x) (x = 0, 0.25, 0.5, 0.75, and 1), is investigated by point contact Andreev reflection (PCAR) measurements. While the P values of the ternary Co 2FeGe and Co 2FeGa alloys are 0.58 and 0.59, respectively, the corresponding value for Co 2Fe(Ge 0.5Ga 0.25) is as high as 0.69. Co 2Fe(Ge 0.5Ga 0.5) alloy shows a strong tendency for L2 1 ordering and a high Curie temperature of 807 °C. Ab initio calculations indicate that the band structures of the Co 2FeGe and Co 2Fe(Ge 0.5Ga 0.5) alloys with L2 1 or B2 structures are half-metallic. Thin films of the quaternary Co 2Fe(Ge 0.5Ga 0.5) alloy grown on MgO(0 0 1) substrates order to the L2 1 structure upon annealing at 500 °C, giving rise to a high P of 0.75. This is the highest P value reported for Heusler alloy thin films using the PCAR technique. Ferromagnetic resonance measurements show that the Gilbert damping constant of the film is ∼0.008. All these indicate that the Co 2Fe(Ge 0.5Ga 0.5) alloy is promising as a spin polarized current source for spintronics devices.

本文言語English
ページ(範囲)6257-6265
ページ数9
ジャーナルActa Materialia
60
18
DOI
出版ステータスPublished - 2012 10
外部発表はい

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • セラミックおよび複合材料
  • ポリマーおよびプラスチック
  • 金属および合金

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