Properties of Josephson tunnel junction with trapped Abrikosov vortices: physical aspects and application for registration of alpha-particles

Properties of the Nb/AlO/sub x//Nb Josephson tunnel junction (JTJ) with Abrikosov vortices (AVs) trapped in electrodes were investigated. The trapping of AVs is performed by a field-cooling process when the JTJ is cooled through the critical temperature T/sub c/ either in applied perpendicular magnetic field (B/sub perpendicular to /) (mode 1) or by application of the perpendicular magnetic field B/sub perpendicular to / when the JTJ is at the temperature below T/sub c/ (mode 2). The effect of AVs on dependences of Josephson critical supercurrent I/sub c/ in the parallel magnetic field B/sub /// is studied. It is found that distortion in I/sub c/-versus-B/sub /// curves in the case of mode 1 differ qualitatively from that in the case of mode 2. These differences can be trapped in electrodes of the JTJ. The influence of alpha -particles on AVs trapped in electrodes of the JTJ is investigated. The results can be explained by the single AV motion caused by alpha -particles. It is believed that the JTJ with trapped AVs could be used as a new type of detector of nuclear particles.