Origin of superconductivity and ferromagnetism in Bi/Ni/Bi sandwich trilayers

ORAL

Abstract

Coexistence of superconductivity and ferromagnetism was experimentally observed in Bi/Ni bilayers [PRL 94, 037006 (2005)]. To reveal the origin of the superconductivity in this system, we here systematically studied the superconductivity and the ferromagnetism in Bi/Ni/Bi trilayers, Bi/Ni bilayers and Ni/Bi bilayers. We found the superconducting transition temperature to be independent of the thickness of Ni layers from 1nm to 45nm in Bi/Ni/Bi trilayers. The superconducting critical magnetic fields of trilayers were higher than those of bilayers. In addition, we observed conventional ferromagnetism in both trilayers and bilayers. These observations can be explained by a model that the superconductivity originates from the Bi/Ni interfaces with spin triplet pairing.

*This research is supported by the NSF grants (DMR-0820404, Penn State MRSEC; DMR-1207469, MIT).

–

Authors

  • Weiwei Zhao

    • Center for Nanoscale Science and Physics Department, PSU

  • Cui-zu Chang

    • Francis Bitter Magnet Lab, MIT

  • Duk-Y Kim

    • Physics Department, PSU

  • Jagadeesh Moodera

    • Francis Bitter Magnet Lab and Physics Department, MIT

  • Moses Chan

    • Center for Nanoscale Science and Physics Department, PSU