Evolution of superconducting critical temperature in asymmetrical F1/F2/S trilayers due to singlet-triplet correlations and external magnetic field

Abstract

We theoretically explore a competition between magnetism and superconductivity for the three-layered ferromagnet/superconductor (F/S) structures. The critical properties of F1/F2/S trilayers in an external parallel magnetic field H are investigated. The different mutual orientations of the F layer magnetizations are examined. Under this condition the triplet component of the superconducting condensate is arisen. Assuming that all layers are dirty we solve boundary problem for the Usadel function. To find the critical parameters for trilayer as function of the F layers thicknesses we use Gor'kov's self-consistency equation. The results of numerical calculations for critical temperature Tc and critical magnetic field Hc at various parameters of F/S structure show that the external magnetic field and triplet correlations can essentially influence on the critical properties of considered systems. Unusual dependencies are discussed.