Stoner enhanced paramagnetic influence on superconductivity in a superconductor/metallic heterostructure

The unusual magnetic behaviour of a Pd/Nb67Ti33/Pd heterostructure was investigated using polarised neutron reflectivity technique. On application of a large in-plane magnetic field, Stoner enhanced paramagnet Pd was found to influence the magnetic state of the Nb67Ti33 layer both above and below the superconducting transition temperature Tc significantly. Unlike the case of a conventional proximity effect for a superconductor/metallic heterostructure, the pair correlation in the superconducting state has been found to be more stable in the higher field limit compared to its low field counterpart, possibly signaturing a ‘novel’ coupled state in the system. The superconducting state in Nb67Ti33 has been found to be diamagnetic in nature at all the fields that can be fitted using a Meissner kind of behaviour in the high field limit. The magnetic properties of Pd and Nb67Ti33 are in excellent agreement with those measured using bulk magnetisation measurements.

► We measured the unusual magnetic behaviour of a Pd/NbTi/Pd trilayer using polarised neutron reflectometry.
► We observed the survival of superconductivity at high magnetic field in the presence of strong magnetic layers.
► The superconducting states are of diamagnetic in nature that can be described using a Meissner kind of behaviour.