Proximity effect between a superconductor and a partially spin-polarized ferromagnet: Case study of the Pb/Cu/Co2Cr1−xFexAl trilayer

• Published in: Physical review. B 2017-07, Vol.96 (2)
• Main Authors: Kamashev, A A, Leksin, P V, Schumann, J, Kataev, V, Thomas, J, Gemming, T, Büchner, B, Garifullin, I A
• Format: Article
• Language: English
• Subjects: Conduction bands; Conduction electrons; Cooper pairs; Electron spin; Electrons; Ferromagnetic materials; Heterostructures; Heusler alloys; Interface stability; Interlayers; Polarization (spin alignment); Proximity effect (electricity); Stability analysis; Superconductivity; Superconductors; Thin films
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.96.024512

We have studied the proximity effect in thin-film heterostructures composed of the superconducting Pb (S) and of the ferromagnetic Heusler alloy Co2Cr1−xFexAl (F) with different degrees of the spin polarization of the conduction band. A thin Cu interlayer is inserted in between the S and F layers to ensure the stability of the S/F interface. The analysis of the dependences of the superconducting transition temperatures in such heterostructures on the thickness of the Pb or of the Heusler alloy using the theory by Fominov et al. [Ya. V. Fominov, N. M. Chtchelkatchev, and A. A. Golubov, Phys. Rev. B 66, 014507 (2002)] shows that, with increasing the exchange splitting of the conduction band of a ferromagnet and, respectively, of the degree of the spin polarization, the probability of transmission of the superconducting Cooper pairs through the S/F interface decreases. We conclude that the spin imbalance plays a key role in the processes taking place at the interface between a superconductor and a ferromagnet with spin-polarized conduction electrons.