Tailoring superconducting states in superconductor-ferromagnet hybrids

Abstract

We present results of a comprehensive investigation of two phenomena arising in superconductor(S)/ferromagnet(F) heterostructures of Nb on FePd with a lateral magnetic domain pattern: domain-superconductivity and spin-triplet Cooper pair generation. Resistivity measurements in a magnetic field applied out-of-plane to a Nb/FePd (S/F) sample with high magnetocrystalline anisotropy give evidence of stray field generated domain-wall- and reverse-domain-superconductivity. A corresponding bilayer comprising low magnetocrystalline anisotropy exhibits spin-triplet Cooper pair generation and a notable high variation of the S critical temperature due to spin-triplet generation (Δ T _c ) of 100 mK in an in-plane applied field. Using reference samples we can clearly distinguish stray field from proximity effects. The relevance of the characteristic S and F length scales related to the observed proximity effects is discussed.

Keywords

• superconductor–ferromagnet heterostructures
• domain-superconductivity
• spin-triplet Cooper pairs
• proximity effect