Interfacial Spin Structure and Spin-Triplet Superconductivity in Magnetic-Superconducting Heterostructures*

Combining superconductivity with spintronics can lead to different superconducting states, which can be useful for spin transport applications. To date, the vast majority of the research on systems that exhibit evidence of spin-triplet superconductivity in hetrostructures has used transport measurements in devices. There is limited research directly probing the nature of the interface and spin structure. Here, we used polarized neutron reflectivity combined with transport measurements to probe the interplay of magnetism and superconductivity in a new spin-triplet spin valve heterostructure with epitaxial growth of Co and Ni thin films as the fixed hard magnetic layer, epitaxial NiFe as the soft magnetic layer, and Nb as the superconductor. Magnetic states of each magnetic layer have been studied using a polarized beam reflectometer. By varying the thickness of the free magnetic layer and the angle of external field, we were able to operate on and off state of the spin-triplet spin valve. Our magnetic heterostructure shows a change in superconducting critical temperature at different angles of external field depending upon the thickness of the free magnetic layer.