Spin switch effect in multiply connected superconductor-ferromagnet hybrid geometry

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): B. KrunavakarnAbstractWe consider a superconducting spin valve in multiply connected superconductor-ferromagnet hybrid geometry such as a superconducting ring enclosed a ferromagnetic metal, in the framework of linearized Usadel equations. We simplify our model by considering the presence of the exchange field in the superconducting ring which allows us to manipulate magnetization orientations in parallel or antiparallel configurations by switching the weaker exchange field. In such geometry the superconducting ground state is activated to higher orbital states characterized by the nonvanishing vorticity parameters L which will be the energetically favorable superconducting state in some ranges of the proximity superconductor-ferromagnet region. The competing effects caused by the exchange interactions and the orbital effect, are analyzed through the nonmonotonic dependence of the superconducting critical temperature Tc on the radius df of the ferromagnetic core. The analytic Tc(df) formula is obtained within the single mode approach and the analysis of the spin switch effect is given.

Source: Physics Letters A - January 22, 2019 Category: Physics Source Type: research