# Fiske Steps and Abrikosov Vortices in Josephson Tunnel Junctions 

Istituto di Cibernetica ”E.Caianiello” del C. N. R., 

Via Campi Flegrei 34, 80078 Pozzuoli, Naples, Italy. 

M. P. Lisitskiy ∗ 

M. V. Fistul 

Theoretische Physik III, Ruhr-Universit¨ at Bochum, D-44801 Bochum, Germany 

(Dated: September 1, 2018) 

## Abstract 

We present a theoretical and experimental study of the Fiske resonances in the current-voltage characteristics of ”small” Josephson junctions with randomly distributed misaligned Abrikosov vortices. We obtained that in the presence of Abrikosov vortices the resonant interaction of elec- tromagnetic waves, excited inside a junction, with the ac Josephson current manifests itself by Fiske steps in a current-voltage characteristics even in the absence of external magnetic field. We found that the voltage positions of the Fiske steps are determined by a junction size , but the Fiske step magnitudes depend both on the density of trapped Abrikosov vortices and on their misalign- ment parameter. We measured the magnetic field dependence of both the amplitude of the first Fiske step and the Josephson critical current of low-dissipative small Nb based Josephson tunnel junctions with artificially introduced Abrikosov vortices. A strong decay of the Josephson critical current and a weak non-monotonic decrease of the first Fiske step amplitude on the Abrikosov vortex density were observed. The experimentally observed dependencies are well described by the developed theory. 

PACS numbers: 74.50.+r, 74.25.Qt 

