Giant Spin-Valve Effect in Heterostructures with a Superconducting Layer

• Published in: JETP letters 2019-09, Vol.110 (5), p.342-347
• Main Authors: Kamashev, A. A., Garif’yanov, N. N., Validov, A. A., Schumann, J., Kataev, V., Büchner, B., Fominov, Ya. V., Garifullin, I. A.
• Format: Article
• Language: English
• Subjects: Atomic; Biological and Medical Physics; Biophysics; Condensed Matter; Cooper pairs; Copper; Dependence; Electrons; Ferromagnetic materials; Heterostructures; Heusler alloys; Molecular; Nickel; Optical and Plasma Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Polarization (spin alignment); Quantum Information Technology; Solid State Physics; Spin valves; Spintronics; Superconductivity
• ISSN: 0021-3640; 1090-6487
• DOI: 10.1134/S0021364019170077

The superconducting characteristics of the spin-valve Co 2 Cr 1 - x Fe x Al y /Cu/Ni/Cu/Pb heterostructures are studied. It is found that the difference in the plots characterizing superconducting transitions at the parallel and perpendicular orientations of magnetizations in the ferromagnetic Heusler alloy layer (HA = Co 2 Cr 1 - x Fe x Al y ) with a high degree of spin polarization and in the nickel (Ni) layer can be as large as 0.5 K. For all samples, the dependence of T c on the angle between the magnetization directions of the ferromagnetic layers exhibits a deep minimum near the orthogonal orientation. This minimum results from the long-range triplet components of the superconducting condensate in a ferromagnetic material. At the perpendicular orientation of the magnetizations, the Heusler alloy layer with the high degree of spin polarization absorbs the spin-polarized Cooper pairs from the spacing between the Heusler alloy and Ni layers.