Magnetic screening in proximity effect Josephson-junction arraysM. Tesei1 and R. Théron2
1 The Blackett Laboratory, Imperial College - London SW7 2BZ, UK, EU
2 Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering IMT, Photovoltaics and thin film electronics laboratory - Neuchâtel, Switzerland
received 2 July 2008; accepted in final form 2 March 2009; published March 2009
published online 8 April 2009
The modulation with magnetic field of the sheet inductance measured on proximity effect Josephson-junction arrays (JJAs) is progressively vanishing on lowering the temperature, leading to a low-temperature field-independent response. This behaviour is consistent with the decrease of the two-dimensional penetration length below the lattice parameter. Low-temperature data are quantitatively compared with theoretical predictions based on the XY model in the absence of thermal fluctuations. The results show that the description of a JJA within the XY model is incomplete and the system is put well beyond the weak screening limit which is usually assumed in order to invoke the well-known frustrated XY model describing classical Josephson-junction arrays.
74.81.Fa - Josephson junction arrays and wire networks.
74.25.Ha - Magnetic properties.
64.60.De - Statistical mechanics of model systems (Ising model, Potts model, field-theory models, Monte Carlo techniques, etc.).
© EPLA 2009