Detection of small exchange fields in S/F structures

A.S. Vasenko, S. Kawabata, A. Ozaeta, Alexandre Avraamovitch Golubov, V.S. Stolyarov, F.S. Bergeret, F.W.J. Hekking

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Scopus)

Abstract

Ferromagnetic materials with exchange fields EexEex smaller or of the order of the superconducting gap ΔΔ are important for applications of corresponding (s-wave) superconductor/ferromagnet/superconductor (SFS) junctions. Presently such materials are not known but there are several proposals how to create them. Small exchange fields are in principle difficult to detect. Based on our results we propose reliable detection methods of such small EexEex. For exchange fields smaller than the superconducting gap the subgap differential conductance of the normal metal–ferromagnet–insulator–superconductor (NFIS) junction shows a peak at the voltage bias equal to the exchange field of the ferromagnetic layer, eV=EexeV=Eex. Thus measuring the subgap conductance one can reliably determine small Eex<ΔEex<Δ. In the opposite case Eex>ΔEex>Δ one can determine the exchange field in scanning tunneling microscopy (STM) experiment. The density of states of the FS bilayer measured at the outer border of the ferromagnet shows a peak at the energy equal to the exchange field, E=EexE=Eex. This peak can be only visible for small enough exchange fields of the order of few ΔΔ.
Original languageEnglish
Pages (from-to)175-179
JournalJournal of magnetism and magnetic materials
Volume383
DOIs
Publication statusPublished - 1 Nov 2015

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Superconducting materials
Ferromagnetic materials
Scanning tunneling microscopy
Bias voltage
ferromagnetic materials
borders
proposals
scanning tunneling microscopy
Experiments
electric potential
energy

Keywords

  • METIS-307828
  • IR-93523

Cite this

Vasenko, A. S., Kawabata, S., Ozaeta, A., Golubov, A. A., Stolyarov, V. S., Bergeret, F. S., & Hekking, F. W. J. (2015). Detection of small exchange fields in S/F structures. Journal of magnetism and magnetic materials, 383, 175-179. https://doi.org/10.1016/j.jmmm.2014.11.009
Vasenko, A.S. ; Kawabata, S. ; Ozaeta, A. ; Golubov, Alexandre Avraamovitch ; Stolyarov, V.S. ; Bergeret, F.S. ; Hekking, F.W.J. / Detection of small exchange fields in S/F structures. In: Journal of magnetism and magnetic materials. 2015 ; Vol. 383. pp. 175-179.
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Vasenko, AS, Kawabata, S, Ozaeta, A, Golubov, AA, Stolyarov, VS, Bergeret, FS & Hekking, FWJ 2015, 'Detection of small exchange fields in S/F structures' Journal of magnetism and magnetic materials, vol. 383, pp. 175-179. https://doi.org/10.1016/j.jmmm.2014.11.009

Detection of small exchange fields in S/F structures. / Vasenko, A.S.; Kawabata, S.; Ozaeta, A.; Golubov, Alexandre Avraamovitch; Stolyarov, V.S.; Bergeret, F.S.; Hekking, F.W.J.

In: Journal of magnetism and magnetic materials, Vol. 383, 01.11.2015, p. 175-179.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Detection of small exchange fields in S/F structures

AU - Vasenko, A.S.

AU - Kawabata, S.

AU - Ozaeta, A.

AU - Golubov, Alexandre Avraamovitch

AU - Stolyarov, V.S.

AU - Bergeret, F.S.

AU - Hekking, F.W.J.

N1 - Selected papers from the sixth Moscow International Symposium on Magnetism (MISM-2014)

PY - 2015/11/1

Y1 - 2015/11/1

N2 - Ferromagnetic materials with exchange fields EexEex smaller or of the order of the superconducting gap ΔΔ are important for applications of corresponding (s-wave) superconductor/ferromagnet/superconductor (SFS) junctions. Presently such materials are not known but there are several proposals how to create them. Small exchange fields are in principle difficult to detect. Based on our results we propose reliable detection methods of such small EexEex. For exchange fields smaller than the superconducting gap the subgap differential conductance of the normal metal–ferromagnet–insulator–superconductor (NFIS) junction shows a peak at the voltage bias equal to the exchange field of the ferromagnetic layer, eV=EexeV=Eex. Thus measuring the subgap conductance one can reliably determine small Eex<ΔEex<Δ. In the opposite case Eex>ΔEex>Δ one can determine the exchange field in scanning tunneling microscopy (STM) experiment. The density of states of the FS bilayer measured at the outer border of the ferromagnet shows a peak at the energy equal to the exchange field, E=EexE=Eex. This peak can be only visible for small enough exchange fields of the order of few ΔΔ.

AB - Ferromagnetic materials with exchange fields EexEex smaller or of the order of the superconducting gap ΔΔ are important for applications of corresponding (s-wave) superconductor/ferromagnet/superconductor (SFS) junctions. Presently such materials are not known but there are several proposals how to create them. Small exchange fields are in principle difficult to detect. Based on our results we propose reliable detection methods of such small EexEex. For exchange fields smaller than the superconducting gap the subgap differential conductance of the normal metal–ferromagnet–insulator–superconductor (NFIS) junction shows a peak at the voltage bias equal to the exchange field of the ferromagnetic layer, eV=EexeV=Eex. Thus measuring the subgap conductance one can reliably determine small Eex<ΔEex<Δ. In the opposite case Eex>ΔEex>Δ one can determine the exchange field in scanning tunneling microscopy (STM) experiment. The density of states of the FS bilayer measured at the outer border of the ferromagnet shows a peak at the energy equal to the exchange field, E=EexE=Eex. This peak can be only visible for small enough exchange fields of the order of few ΔΔ.

KW - METIS-307828

KW - IR-93523

U2 - 10.1016/j.jmmm.2014.11.009

DO - 10.1016/j.jmmm.2014.11.009

M3 - Article

VL - 383

SP - 175

EP - 179

JO - Journal of magnetism and magnetic materials

JF - Journal of magnetism and magnetic materials

SN - 0304-8853

ER -