title: Large Superconducting Spin Valve Effect and Ultrasmall Exchange Splitting in Epitaxial Rare-Earth-Niobium Trilayers.
abstract: Epitaxial Ho/Nb/Ho and Dy/Nb/Dy superconducting spin valves show a reversible change in the zero-field critical temperature (ΔT(c0)) of ∼400  mK and an infinite magnetoresistance on changing the relative magnetization of the Ho or Dy layers. Unlike transition-metal superconducting spin valves, which show much smaller ΔT(c0) values, our results can be quantitatively modeled. However, the fits require an extraordinarily low induced exchange splitting which is dramatically lower than known values for rare-earth Fermi-level electrons, implying that new models for the magnetic proximity effect may be required.
authors: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.
authors: Yuanzhou
authors: Y
authors: Gu
authors: Theoretical Physics, Oxford University, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
authors: Gábor B
authors: GB
authors: Halász
authors: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.
authors: J W A
authors: JW
authors: Robinson
authors: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.
authors: M G
authors: MG
authors: Blamire