Superconductivity at ferromagnetic domain walls in hybrid InAs/EuS/Al nanowires. Part 2: studied by magneto-transport*

The effect of magnetism on superconductivity shows dramatically in ferromagnet/superconductor bilayers. Magnetic domains in the ferromagnet destroy Cooper pairs in the superconductor, while domain walls preserve them [1]. As the spin of the surviving Cooper pairs is expected to depend on the underlying magnetic texture, the integration of the bilayer films with semiconductors can serve as basis for novel devices such as spin-triplet Josephson junctions.

 

Here we characterize domain wall superconductivity (DWS) in bilayers of the magnetic insulator EuS and the superconductor Al fully wrapped around InAs semiconductor nanowires [2]. The characterization consists of magnetoresistance measurements done in individual nanowire devices in a dilution refrigerator, which complements scanning SQUID imaging of the magnetic properties of the individual nanowires presented in Part I of this work.

 

The dependence of the resistance on magnetic field strength and angle indicates the presence of DWS islands on top of vortex magnetic domain walls along the nanowires. Resistance jumps in time corroborate the discreteness of the superconductivity.

 

[1] Yang, Z. et al. (2004). Nat. Mater. 3, 793–798.

[2] Liu, Y. et al. (2020). Nano Lett. 20, 456–462.