Spontaneous Supercurrent Induced by Ferromagnetic π Junctions

A. Bauer, J. Bentner, M. Aprili, M. L. Della Rocca, M. Reinwald, W. Wegscheider, and C. Strunk
Phys. Rev. Lett. 92, 217001 – Published 26 May 2004

Abstract

We present magnetization measurements of mesoscopic superconducting niobium loops containing a ferromagnetic (PdNi) π junction. The loops are prepared on top of the active area of a micro-Hall sensor based on high mobility GaAs/AlGaAs heterostructures. We observe asymmetric switching of the loop between different magnetization states when reversing the sweep direction of the magnetic field. This provides evidence for a spontaneous current induced by the intrinsic phase shift of the π junction. In addition, the presence of the spontaneous current near zero applied field is directly revealed by an increase of the magnetic moment with decreasing temperature, which results in half integer flux quantization in the loop at low temperatures.

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  • Received 4 December 2003

DOI:https://doi.org/10.1103/PhysRevLett.92.217001

©2004 American Physical Society

Authors & Affiliations

A. Bauer1, J. Bentner1, M. Aprili2, M. L. Della Rocca2, M. Reinwald1, W. Wegscheider1, and C. Strunk1,*

  • 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany
  • 2CSNSM-CNRS, Université Paris-Sud, 91405 Orsay Cedex, France†

  • *Electronic address: christoph.strunk@physik.uni-regensburg.de
  • Also at LPQ-ESPCI, 75005 Paris, France.

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Vol. 92, Iss. 21 — 28 May 2004

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