Epitaxial contact Andreev reflection spectroscopy of NbN/Co2FeSi layered devices

Iduru Shigeta (Corresponding Author), Takahide Kubota, Yuya Sakuraba, Cor G. Molenaar, Joost N. Beukers, Shojiro Kimura, Alexander A. Golubov, Alexander Brinkman, Satoshi Awaji, Koki Takanashi, Masahiko Hiroi

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Abstract

We investigated the spin polarization P of Co-based Heusler alloy Co2FeSi by epitaxial contact Andreev reflection (ECAR) spectroscopy using epitaxially grown superconductor NbN and Heusler alloy Co2FeSi layered devices. Ferromagnetic Co2FeSi possesses the highest Curie temperature (TC ? 1100 K) and the largest spontaneous magnetic moment (ps ? 6 μB) in the class of Heusler alloys. The ECAR measurements revealed that the P value of Co2FeSi was 54 ± 2% with a finite barrier parameter Z, indicating that an intrinsic P value in ECAR spectroscopy would exceed reported values in point-contact Andreev reflection spectroscopy. We therefore established not only the epitaxial integration of ferromagnetic Co2FeSi with superconductor NbN on an MgO substrate but also the fabrication and evaluation techniques of their ECAR devices. This highly versatile superconducting spintronic system enables fundamental superconducting spintronic studies, and it is also a candidate for practical superconducting spintronic devices.

Original languageEnglish
Article number072402
JournalApplied physics letters
Volume112
Issue number7
DOIs
Publication statusPublished - 12 Feb 2018

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spectroscopy
superconducting devices
Curie temperature
magnetic moments
fabrication
evaluation
polarization

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Shigeta, I., Kubota, T., Sakuraba, Y., Molenaar, C. G., Beukers, J. N., Kimura, S., ... Hiroi, M. (2018). Epitaxial contact Andreev reflection spectroscopy of NbN/Co2FeSi layered devices. Applied physics letters, 112(7), [072402]. https://doi.org/10.1063/1.5007287
Shigeta, Iduru ; Kubota, Takahide ; Sakuraba, Yuya ; Molenaar, Cor G. ; Beukers, Joost N. ; Kimura, Shojiro ; Golubov, Alexander A. ; Brinkman, Alexander ; Awaji, Satoshi ; Takanashi, Koki ; Hiroi, Masahiko. / Epitaxial contact Andreev reflection spectroscopy of NbN/Co2FeSi layered devices. In: Applied physics letters. 2018 ; Vol. 112, No. 7.
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abstract = "We investigated the spin polarization P of Co-based Heusler alloy Co2FeSi by epitaxial contact Andreev reflection (ECAR) spectroscopy using epitaxially grown superconductor NbN and Heusler alloy Co2FeSi layered devices. Ferromagnetic Co2FeSi possesses the highest Curie temperature (TC ? 1100 K) and the largest spontaneous magnetic moment (ps ? 6 μB) in the class of Heusler alloys. The ECAR measurements revealed that the P value of Co2FeSi was 54 ± 2{\%} with a finite barrier parameter Z, indicating that an intrinsic P value in ECAR spectroscopy would exceed reported values in point-contact Andreev reflection spectroscopy. We therefore established not only the epitaxial integration of ferromagnetic Co2FeSi with superconductor NbN on an MgO substrate but also the fabrication and evaluation techniques of their ECAR devices. This highly versatile superconducting spintronic system enables fundamental superconducting spintronic studies, and it is also a candidate for practical superconducting spintronic devices.",
author = "Iduru Shigeta and Takahide Kubota and Yuya Sakuraba and Molenaar, {Cor G.} and Beukers, {Joost N.} and Shojiro Kimura and Golubov, {Alexander A.} and Alexander Brinkman and Satoshi Awaji and Koki Takanashi and Masahiko Hiroi",
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Shigeta, I, Kubota, T, Sakuraba, Y, Molenaar, CG, Beukers, JN, Kimura, S, Golubov, AA, Brinkman, A, Awaji, S, Takanashi, K & Hiroi, M 2018, 'Epitaxial contact Andreev reflection spectroscopy of NbN/Co2FeSi layered devices' Applied physics letters, vol. 112, no. 7, 072402. https://doi.org/10.1063/1.5007287

Epitaxial contact Andreev reflection spectroscopy of NbN/Co2FeSi layered devices. / Shigeta, Iduru (Corresponding Author); Kubota, Takahide; Sakuraba, Yuya; Molenaar, Cor G.; Beukers, Joost N.; Kimura, Shojiro; Golubov, Alexander A.; Brinkman, Alexander; Awaji, Satoshi; Takanashi, Koki; Hiroi, Masahiko.

In: Applied physics letters, Vol. 112, No. 7, 072402, 12.02.2018.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Epitaxial contact Andreev reflection spectroscopy of NbN/Co2FeSi layered devices

AU - Shigeta, Iduru

AU - Kubota, Takahide

AU - Sakuraba, Yuya

AU - Molenaar, Cor G.

AU - Beukers, Joost N.

AU - Kimura, Shojiro

AU - Golubov, Alexander A.

AU - Brinkman, Alexander

AU - Awaji, Satoshi

AU - Takanashi, Koki

AU - Hiroi, Masahiko

PY - 2018/2/12

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N2 - We investigated the spin polarization P of Co-based Heusler alloy Co2FeSi by epitaxial contact Andreev reflection (ECAR) spectroscopy using epitaxially grown superconductor NbN and Heusler alloy Co2FeSi layered devices. Ferromagnetic Co2FeSi possesses the highest Curie temperature (TC ? 1100 K) and the largest spontaneous magnetic moment (ps ? 6 μB) in the class of Heusler alloys. The ECAR measurements revealed that the P value of Co2FeSi was 54 ± 2% with a finite barrier parameter Z, indicating that an intrinsic P value in ECAR spectroscopy would exceed reported values in point-contact Andreev reflection spectroscopy. We therefore established not only the epitaxial integration of ferromagnetic Co2FeSi with superconductor NbN on an MgO substrate but also the fabrication and evaluation techniques of their ECAR devices. This highly versatile superconducting spintronic system enables fundamental superconducting spintronic studies, and it is also a candidate for practical superconducting spintronic devices.

AB - We investigated the spin polarization P of Co-based Heusler alloy Co2FeSi by epitaxial contact Andreev reflection (ECAR) spectroscopy using epitaxially grown superconductor NbN and Heusler alloy Co2FeSi layered devices. Ferromagnetic Co2FeSi possesses the highest Curie temperature (TC ? 1100 K) and the largest spontaneous magnetic moment (ps ? 6 μB) in the class of Heusler alloys. The ECAR measurements revealed that the P value of Co2FeSi was 54 ± 2% with a finite barrier parameter Z, indicating that an intrinsic P value in ECAR spectroscopy would exceed reported values in point-contact Andreev reflection spectroscopy. We therefore established not only the epitaxial integration of ferromagnetic Co2FeSi with superconductor NbN on an MgO substrate but also the fabrication and evaluation techniques of their ECAR devices. This highly versatile superconducting spintronic system enables fundamental superconducting spintronic studies, and it is also a candidate for practical superconducting spintronic devices.

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Shigeta I, Kubota T, Sakuraba Y, Molenaar CG, Beukers JN, Kimura S et al. Epitaxial contact Andreev reflection spectroscopy of NbN/Co2FeSi layered devices. Applied physics letters. 2018 Feb 12;112(7). 072402. https://doi.org/10.1063/1.5007287