In this work we give a characterization of the RF effect of memory switching on Nb-Al/AlOx-(Nb)-Pd0.99Fe0.01-Nb Josephson junctions as a function of magnetic field pulse amplitude and duration, alongside with an electrodynamical characterization of such junctions, in comparison with standard Nb-Al/AlOx-Nb tunnel junctions. The use of microwaves to tune the switching parameters of magnetic Josephson junctions is a step in the development of novel addressing schemes aimed at improving the performances of superconducting memories.

We test the effect of an external RF field on the switching processes of magnetic Josephson junctions (MJJs) suitable for the realization of fast, scalable cryogenic memories compatible with Single Flux Quantum logic. We show that the combined application of microwaves and magnetic field pulses can improve the performances of the device, increasing the separation between the critical current levels corresponding to logical '0' and '1'. The enhancement of the current level separation can be as high as 80% using an optimal set of parameters. We demonstrate that external RF fields can be used as an additional tool to manipulate the memory states, and we expect that this approach may lead to the development of new methods of selecting MJJs and manipulating their states in memory arrays for various applications.

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The magnetoresistance of a domain wall (DWR) is measured in Permalloy constrictions down to a few atoms in size. We find a negative DWR for nanometer-sized constrictions, becoming positive in the atomic-contact regime. We conclude that the contribution from the anisotropic magnetoresistance (AMR) is gradually weakened as size decreases and spinpolarized transport across an atomically narrow constriction dominates the magnetoresistance. This is revealed by a positive contribution to the DWR reaching four percent for the smallest constrictions, which depends significantly on the specifics of the atomic arrangement.