Critical Temperature of Superconducting Magnetic Hybrid Systems*

We study proximity systems made of coupled thin films with superconducting and magnetic ground states. We analyze how varying parameters of the magnetic component affects the superconducting critical temperature T_c of the entire system. Singlet Cooper pairs formed in the superconducting layer permeate into the magnetic material resulting in the generation of triplet pair correlations that may modify T_c. The critical temperature is calculated by solving Usadel’s equations using an involved transformation to an eigenvalue problem. The method is a generalization of previous work that enables us to include magnetic inhomogeneities. We apply the method to a trilayer SF₁F₂ where F₁ and F₂ have different magnetic properties. Specifically, we study the behavior of T_c as a function of the thickness and magnetization twisting angle of F₁ with respect to F₂.