Proximity effects at ferromagnet-superconductor interfaces

Abstract

We study proximity effects at ferromagnet superconductor interfaces by self-consistent numerical solution of the Bogoliubov-de Gennes equations for the continuum, without any approximations. Our procedures allow us to study systems with long superconducting coherence lengths. We obtain results for the pair potential, the pair amplitude, and the local density of states. We use these results to extract the relevant proximity lengths. We find that the superconducting correlations in the ferromagnet exhibit a damped oscillatory behavior that is reflected in both the pair amplitude and the local density of states. The characteristic length scale of these oscillations is approximately inversely proportional to the exchange field, and is independent of the superconducting coherence length in the range studied. We find the superconducting coherence length to be nearly independent of the ferromagnetic polarization. 74.50.+r, 74.25.Fy, 74.80.Fp

Josephson effect in double-barrier superconductor-ferromagnet junctions

“…Performing integration over k || and using Eqs. (13) and (19), for the Josephson current in a planar SIFIS junction we get…”

Crossed Andreev reflection in structures consisting of a superconductor with ferromagnetic leads

“…Throughout this paper, we neglect the impurity scattering in SC and the proximity effect near the interfaces. 33,47,48,49,50,51 The solution of the BdG equation in the SC region is given by…”

Andreev bound states in ferromagnet-superconductor nanostructures

“…The F M order parameter (spin polarization) shows the usual Meissner -like behavior in the SC [19], while the SC pairing amplitude oscillates as we increase the thickness of the F M slab [16]- [18]. Similar oscillations are found if we fix the thickness of the F M sample and change the exchange splitting [19].…”

“…Similarly in the F M/SC heterostructures: the oscillations of the pairing amplitude have been predicted [15]- [18] as well as spontaneously generated current in the ground state [19]. These features give a strong evidence that the F F LO state is really realized in F M/SC nanostructures.…”