MAGNETIC-FIELD DEPENDENCE OF FISKE RESONANCES IN NB P-TYPE INAS/NB WEAK LINKS/

We present measurements of the temperature and magnetic-field dependen ce of the critical current Ic in Nb/InAs/Nb weak links. We also report on the magnetic-field dependence of resonances in the current-voltage (I-V) characteristics, the so-called Fiske resonances. Their magnetic -held dependence can be explained by a simplified resistively shunted junction (RSJ) model. We also measure a Fiske resonance with a period half as large as the period of the corresponding Fraunhofer pattern. T his cannot be understood within the simplified RSJ model. It may be re lated to deviations From the sinusoidal phase dependence of the critic al current in this type of weak link. (C) 1998 Elsevier Science Ltd. A ll rights reserved.