Superconducting spintronics: state of the art and prospects

Significant progress has been achieved recently in a new field of low-temperature electronics, the physics of superconducting hybrid systems based on superconductors (Ss) and ferromagnets (Fs), which is known as superconducting spintron„ics. We present theoretical and experimental results on studies of the proximity effect with a ferromagnet, which forms an unusual superconducting state in the vicinity of the S/F interface and allows controlling dissipationless charge and spin transport in hybrid structures by changing the texture and properties of the magnetic subsystem. Particular attention is devoted to the properties of the generation of spin-triplet Cooper pairs at the S/F interface that ensure the most efficient interplay between superconductivity and ferromagnetism, including in systems with full spin-polarization of bands (semimetals) and considerable spin–orbit coupling. Problems with the electrodynamics of S/F structures, which have not been covered by previous reviews on superconducting spintronics, are discussed in detail, including the features of the formation of inhomogeneous superconducting and magnetic states due to spin–orbit coupling, long-range triplet correlations in ferromagnets, the electrodynamic proximity effect, and Larkin–Ovchinnikov–Fulde–Ferrell-type instability with a modulation vector in the plane of S/F structure layers. We also discuss the current state of experimental work and promising theoretical concepts and problems relevant to the further development of superconducting spintronics.