Long-range proximity effect in Nb-based heterostructures induced by a magnetically inhomogeneous permalloy layer. (20th February 2017)

• Record Type: Journal Article
• Authors: Cirillo, C; Voltan, S; Ilyina, E A; Hernández, J M; García-Santiago, A; Aarts, J; Attanasio, C
• Is Part Of: New journal of physics. Volume 19:Number 2(2017:Feb.)
• Publication Date: 2017-02-20
• Subjects: superconductivity -- magnetism -- heterostructures -- proximity effect -- dimensional crossover; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aa5de8
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: Odd-frequency triplet Cooper pairs are believed to be the carriers of long-range superconducting correlations in ferromagnets. Such triplet pairs are generated by an inhomogeneous magnetism at the interface between a superconductor (S) and a ferromagnet (F). So far, reproducible long-range effects were reported only in complex layered structures designed to provide the magnetic inhomogeneity. Here we show that spin triplet pair formation can be found in simple unstructured Nb/permalloy ( Py = Ni 0.8 Fe 0.2 )/Nb trilayers and Nb/Py bilayers, but only when the thickness of the ferromagnetic layer ranges between 140 and 250 nm. The effect is related to the emergence of an intrinsically inhomogeneous magnetic state, which is a precursor of the well-known stripe regime in Py that in our samples sets in at thickness larger than 300 nm.