Fabrication of multiband MgB2 tunnel junctions for transport measurements

M. van Zalk, Alexander Brinkman, Alexandre Avraamovitch Golubov, Johannes W.M. Hilgenkamp, T.H. Kim, J.S. Moodera, Horst Rogalla

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

The coexistence of multiple superconducting condensates in a material gives rise to intriguing phenomena, such as the possible presence of number-phase fluctuations. In this work, tunnel junctions were fabricated, aiming for the detection of such phenomena. Planar junctions with normal conducting and superconducting counter-electrodes have been realized. It was found from spectroscopic investigations that the MgO barrier used for the planar junctions is not ideal. To optimize for the two-band behaviour of MgB2, ab-plane ramp-type MgB2 tunnel junctions were fabricated. The use of Al2O3 barriers substantially improved the homogeneity of the junctions, as was concluded from the nearly ideal magnetic field dependence of the critical current and excellent scaling of the junction properties with the junction widths. The current–voltage characteristics show clear Shapiro steps under microwave irradiation. However, the spectrum showed a degradation of the MgB2 in the ramp region and the signature of the σ-gap was absent. For tunnel junction spectroscopy in the ab-direction and the detection of new, two-band related modes, the fabrication process still has to be further optimized.
Original languageUndefined
Pages (from-to)S226-S230
JournalSuperconductor science and technology
Volume19
Issue number5
DOIs
Publication statusPublished - 2006

Keywords

  • IR-74459
  • METIS-233376

Cite this

@article{ef52a13e327b4324aa07b8d3905fd740,
title = "Fabrication of multiband MgB2 tunnel junctions for transport measurements",
abstract = "The coexistence of multiple superconducting condensates in a material gives rise to intriguing phenomena, such as the possible presence of number-phase fluctuations. In this work, tunnel junctions were fabricated, aiming for the detection of such phenomena. Planar junctions with normal conducting and superconducting counter-electrodes have been realized. It was found from spectroscopic investigations that the MgO barrier used for the planar junctions is not ideal. To optimize for the two-band behaviour of MgB2, ab-plane ramp-type MgB2 tunnel junctions were fabricated. The use of Al2O3 barriers substantially improved the homogeneity of the junctions, as was concluded from the nearly ideal magnetic field dependence of the critical current and excellent scaling of the junction properties with the junction widths. The current–voltage characteristics show clear Shapiro steps under microwave irradiation. However, the spectrum showed a degradation of the MgB2 in the ramp region and the signature of the σ-gap was absent. For tunnel junction spectroscopy in the ab-direction and the detection of new, two-band related modes, the fabrication process still has to be further optimized.",
keywords = "IR-74459, METIS-233376",
author = "{van Zalk}, M. and Alexander Brinkman and Golubov, {Alexandre Avraamovitch} and Hilgenkamp, {Johannes W.M.} and T.H. Kim and J.S. Moodera and Horst Rogalla",
year = "2006",
doi = "10.1088/0953-2048/19/5/S13",
language = "Undefined",
volume = "19",
pages = "S226--S230",
journal = "Superconductor science and technology",
issn = "0953-2048",
publisher = "IOP Publishing Ltd.",
number = "5",

}

Fabrication of multiband MgB2 tunnel junctions for transport measurements. / van Zalk, M.; Brinkman, Alexander; Golubov, Alexandre Avraamovitch; Hilgenkamp, Johannes W.M.; Kim, T.H.; Moodera, J.S.; Rogalla, Horst.

In: Superconductor science and technology, Vol. 19, No. 5, 2006, p. S226-S230.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Fabrication of multiband MgB2 tunnel junctions for transport measurements

AU - van Zalk, M.

AU - Brinkman, Alexander

AU - Golubov, Alexandre Avraamovitch

AU - Hilgenkamp, Johannes W.M.

AU - Kim, T.H.

AU - Moodera, J.S.

AU - Rogalla, Horst

PY - 2006

Y1 - 2006

N2 - The coexistence of multiple superconducting condensates in a material gives rise to intriguing phenomena, such as the possible presence of number-phase fluctuations. In this work, tunnel junctions were fabricated, aiming for the detection of such phenomena. Planar junctions with normal conducting and superconducting counter-electrodes have been realized. It was found from spectroscopic investigations that the MgO barrier used for the planar junctions is not ideal. To optimize for the two-band behaviour of MgB2, ab-plane ramp-type MgB2 tunnel junctions were fabricated. The use of Al2O3 barriers substantially improved the homogeneity of the junctions, as was concluded from the nearly ideal magnetic field dependence of the critical current and excellent scaling of the junction properties with the junction widths. The current–voltage characteristics show clear Shapiro steps under microwave irradiation. However, the spectrum showed a degradation of the MgB2 in the ramp region and the signature of the σ-gap was absent. For tunnel junction spectroscopy in the ab-direction and the detection of new, two-band related modes, the fabrication process still has to be further optimized.

AB - The coexistence of multiple superconducting condensates in a material gives rise to intriguing phenomena, such as the possible presence of number-phase fluctuations. In this work, tunnel junctions were fabricated, aiming for the detection of such phenomena. Planar junctions with normal conducting and superconducting counter-electrodes have been realized. It was found from spectroscopic investigations that the MgO barrier used for the planar junctions is not ideal. To optimize for the two-band behaviour of MgB2, ab-plane ramp-type MgB2 tunnel junctions were fabricated. The use of Al2O3 barriers substantially improved the homogeneity of the junctions, as was concluded from the nearly ideal magnetic field dependence of the critical current and excellent scaling of the junction properties with the junction widths. The current–voltage characteristics show clear Shapiro steps under microwave irradiation. However, the spectrum showed a degradation of the MgB2 in the ramp region and the signature of the σ-gap was absent. For tunnel junction spectroscopy in the ab-direction and the detection of new, two-band related modes, the fabrication process still has to be further optimized.

KW - IR-74459

KW - METIS-233376

U2 - 10.1088/0953-2048/19/5/S13

DO - 10.1088/0953-2048/19/5/S13

M3 - Article

VL - 19

SP - S226-S230

JO - Superconductor science and technology

JF - Superconductor science and technology

SN - 0953-2048

IS - 5

ER -