The antiferromagnet/superconductor proximity effect in Cr/V/Cr trilayers

Abstract

We have studied the superconducting properties of (110) textured Cr/V/Cr trilayers grown on Al2O3(1120), representing an antiferromagnet/superconductor (AF/SC) proximity system. We have prepared several series of samples with either dv, the thickness of the V layer, or dCr, the thickness of the Cr layer being constant, while varying the other thickness. We find an overall good agreement with the classical Werthamer theory of the AF/SC proximity effect, with one noticeable exception. When plotting the superconducting transition temperature as a function of the thickness dCr, we find an anomalous drop of Tc(dCr) at dCr ≈ 6 nm with a sudden quenching of the superconductivity for layer thicknesses dCr ≥ 6 nm. We argue that this drop of Tc might be correlated with the onset of an incommensurate spin density wave state in the Cr film.