Spin polarization of Co-Fe alloys estimated by point contact Andreev reflection and tunneling magnetoresistance

S. V. Karthik; T. M. Nakatani; A. Rajanikanth; Y. K. Takahashi; K. Hono

doi:10.1063/1.3058699

Spin polarization of Co-Fe alloys estimated by point contact Andreev reflection and tunneling magnetoresistance

S. V. Karthik, T. M. Nakatani, A. Rajanikanth, Y. K. Takahashi, K. Hono

Research output: Contribution to journal › Article › peer-review

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Abstract

The compositional dependence on spin polarization of Co100-x Fex alloys has been studied by point contact Andreev reflection (PCAR) and tunneling magnetoresistance (TMR) measurements. The intrinsic spin polarization for bcc Co75 Fe25 alloy is P=0.58±0.03 at 4.2 K contrary to the pure Fe (P=0.46±0.03) and Co (P=0.45±0.03). The tunneling spin polarization values of Co75 Fe25 (110) textured polycrystalline electrode and (001) epitaxially grown electrode was estimated to be PT =0.5±0.01 and PT =0.57±0.01 at 8 K from the TMR ratios using Julliere's model for the MTJs prepared on oxidized Si and MgO (001) substrates. The spin polarization obtained from the tunneling junctions and PCAR experiments have been discussed.

Original language	English
Article number	07C916
Journal	Journal of Applied Physics
Volume	105
Issue number	7
DOIs	https://doi.org/10.1063/1.3058699
Publication status	Published - 2009
Externally published	Yes

ASJC Scopus subject areas

Physics and Astronomy(all)

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@article{2ac145125f714ff0be9ffb6579a44f6c,

title = "Spin polarization of Co-Fe alloys estimated by point contact Andreev reflection and tunneling magnetoresistance",

abstract = "The compositional dependence on spin polarization of Co100-x Fex alloys has been studied by point contact Andreev reflection (PCAR) and tunneling magnetoresistance (TMR) measurements. The intrinsic spin polarization for bcc Co75 Fe25 alloy is P=0.58±0.03 at 4.2 K contrary to the pure Fe (P=0.46±0.03) and Co (P=0.45±0.03). The tunneling spin polarization values of Co75 Fe25 (110) textured polycrystalline electrode and (001) epitaxially grown electrode was estimated to be PT =0.5±0.01 and PT =0.57±0.01 at 8 K from the TMR ratios using Julliere's model for the MTJs prepared on oxidized Si and MgO (001) substrates. The spin polarization obtained from the tunneling junctions and PCAR experiments have been discussed.",

author = "Karthik, {S. V.} and Nakatani, {T. M.} and A. Rajanikanth and Takahashi, {Y. K.} and K. Hono",

note = "Funding Information: S.V.K, A.R, and T.M.N would like to acknowledge the National Institute for Materials Science (NIMS) for providing NIMS post doctorate fellowship, ICYS-MANA fellowship, and NIMS junior research assistantship, respectively. This work was in part supported by a Grant-in-Aid for Scientific Research in Priority Area “Creation and control of spin current” and by the World Premier International Research Center Initiative (WPI Initiative) on Materials Nanoarchitronics, MEXT, Japan.",

year = "2009",

doi = "10.1063/1.3058699",

language = "English",

volume = "105",

journal = "Journal of Applied Physics",

issn = "0021-8979",

publisher = "American Institute of Physics Publising LLC",

number = "7",

}

TY - JOUR

T1 - Spin polarization of Co-Fe alloys estimated by point contact Andreev reflection and tunneling magnetoresistance

AU - Karthik, S. V.

AU - Nakatani, T. M.

AU - Rajanikanth, A.

AU - Takahashi, Y. K.

AU - Hono, K.

N1 - Funding Information: S.V.K, A.R, and T.M.N would like to acknowledge the National Institute for Materials Science (NIMS) for providing NIMS post doctorate fellowship, ICYS-MANA fellowship, and NIMS junior research assistantship, respectively. This work was in part supported by a Grant-in-Aid for Scientific Research in Priority Area “Creation and control of spin current” and by the World Premier International Research Center Initiative (WPI Initiative) on Materials Nanoarchitronics, MEXT, Japan.

PY - 2009

Y1 - 2009

N2 - The compositional dependence on spin polarization of Co100-x Fex alloys has been studied by point contact Andreev reflection (PCAR) and tunneling magnetoresistance (TMR) measurements. The intrinsic spin polarization for bcc Co75 Fe25 alloy is P=0.58±0.03 at 4.2 K contrary to the pure Fe (P=0.46±0.03) and Co (P=0.45±0.03). The tunneling spin polarization values of Co75 Fe25 (110) textured polycrystalline electrode and (001) epitaxially grown electrode was estimated to be PT =0.5±0.01 and PT =0.57±0.01 at 8 K from the TMR ratios using Julliere's model for the MTJs prepared on oxidized Si and MgO (001) substrates. The spin polarization obtained from the tunneling junctions and PCAR experiments have been discussed.

AB - The compositional dependence on spin polarization of Co100-x Fex alloys has been studied by point contact Andreev reflection (PCAR) and tunneling magnetoresistance (TMR) measurements. The intrinsic spin polarization for bcc Co75 Fe25 alloy is P=0.58±0.03 at 4.2 K contrary to the pure Fe (P=0.46±0.03) and Co (P=0.45±0.03). The tunneling spin polarization values of Co75 Fe25 (110) textured polycrystalline electrode and (001) epitaxially grown electrode was estimated to be PT =0.5±0.01 and PT =0.57±0.01 at 8 K from the TMR ratios using Julliere's model for the MTJs prepared on oxidized Si and MgO (001) substrates. The spin polarization obtained from the tunneling junctions and PCAR experiments have been discussed.

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DO - 10.1063/1.3058699

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Spin polarization of Co-Fe alloys estimated by point contact Andreev reflection and tunneling magnetoresistance

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