2Vasyl’ Stus Donetsk National University, Vinnytsia 021021, Ukraine
Received Jule 11, 2017
Effect of the thickness of a nanoscale layer of ferromagnetic nickel in direct contact with a superconductor on the density of quasiparticle states of a lead film, a conventional superconductor with singlet pairing of electrons, has been studied (reverse proximity effect). It was found that the penetration depth of superconducting correlations into ferromagnetic nickel is of the same order of magnitude as that in contacts of lead with a normal metal. Such behavior can be explained by the emergence of an inhomogeneous ex-change-field which leads to an effective conversion of spin-singlet (rapidly decaying into a ferromagnetic) Cooper pairs into spin-triplet ones, stable with respect to the exchange interaction.
PACS: 74.78.–w Superconducting films and low-dimensional structures; PACS: 75.50.Cc Other ferromagnetic metals and alloys; PACS: 74.45.+c Proximity effects; Andreev reflection; PACS: 74.55.+v Tunneling phenomena: single particle tunneling and STM.