Superconductivity as a probe of magnetic switching and ferromagnetic stability in Nb/Ni multilayers

L. E. De Long, S. A. Kryukov, A. Bosomtwi, Wentao Xu, E. M. Gonzalez, E. Navarro, J. E. Villegas, J. L. Vicent, Chengtao Yu, M. J. Pechan

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The temperature and field dependences of the AC and DC magnetic moment of superconducting and ferromagnetic Nb/Ni multilayers were measured using a SQUID magnetometer with magnetic field applied parallel to the multilayer plane. Periodic kinks in the superconducting upper critical field are evidence for nucleation of a hierarchy of Abrikosov vortex lattices aligned parallel to the multilayer. Small cusps in the low-field, isothermal DC magnetization are evidence that supercurrents are sensitive to extremely small changes in the Ni layer magnetization. Smooth ferromagnetic hysteresis is observed in the normal state, but is supplanted below the superconducting transition by two reproducible discontinuities that indicate magnetic switching of the Ni layers is tightly coupled to the supercurrents. The discontinuities are attributed to the non-dipole character of the moment near switching fields and, therefore, cannot be analyzed by standard magnetometer software. Ferromagnetic resonance spectra were measured in parallel and perpendicular DC magnetic fields at room temperature and 4.2K, and resulting data suggest that Ni layers interact magnetically in the superconducting state.

Original languageEnglish
Pages (from-to)2735-2760
Number of pages26
JournalPhilosophical Magazine
Issue number17-18
StatePublished - Jun 11 2006

Bibliographical note

Funding Information:
Research at the University of Kentucky was supported by US DoE Grant #DE-FG02-97ER45653. Research at the Universidad Complutense was supported by a Spanish CICY Grant #MAT02-04543 and ESF VORTEX Program. Research at Miami University was supported by a US DoE Grant #DE-FG02-86ER45281.

ASJC Scopus subject areas

  • Condensed Matter Physics


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