Coupling magnetism to superconductivity in thin films

The antagonist electron spin orders in ferromagnetism and in spin-singlet Cooper pairs mediated superconductivity hamper the application of superconductor/ferromagnet (S/F) thin film heterostructures in low power dissipation spintronics because of the low penetration depth of those Cooper pairs in the ferromagnet. However, at carefully engineered S/F interfaces, equal-spin-triplet Cooper pairs with large penetration depth can be generated. This is the case when the ferromagnet shows in-plane magnetic texture like domains [1], as depicted in the figure.

Penetration depth of spin-singlet and spin-triplet Cooper pair components into a Nb/FePd heterostructure with non-collinear magnetization. At the interface, the magnetization rotation leads to a formation of spin-triplet components with SZ = ±1 and large coherence length. Black lines denote spin-singlet components, grey spin-triplet components with SZ = 0 and red spin-triplet components with SZ = ±1.
Penetration depth of spin-singlet and spin-triplet Cooper pair components into a Nb/FePd heterostructure with non-collinear magnetization. At the interface, the magnetization rotation leads to a formation of spin-triplet components with SZ = ±1 and large coherence length. Black lines denote spin-singlet components, grey spin-triplet components with SZ = 0 and red spin-triplet components with SZ = ±1.
Copyright:
—  Forschungszentrum Jülich

References:

  •  A. Stellhorn, A. Sarkar, E. Kentzinger, J. Barthel, A. Di Bernardo, S. Nandi, P. Zakalek, J. Schubert, and T. Brückel, Tailoring superconducting states in superconductor-ferromagnet hybrids, New Journal of Physics 22, 093001 (2020)

Dr. Emmanuel Kentzinger

JCNS-2, PGI-4: Scientific Staff

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  • Quantum Materials and Collective Phenomena (JCNS-2 / PGI-4)
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Last Modified: 05.07.2022