Magnetic oscillations of critical current in intrinsic Josephson-junction stacks

Abstract

A key phenomenon related to the Josephson effect is oscillations of different\nproperties of superconducting tunneling junctions with magnetic field. We\nconsider magnetic oscillations of the critical current in stacks of intrinsic\nJosephson junctions, which are realized in mesas fabricated from layered\nhigh-temperature superconductors. The oscillation behavior is very different\nfrom the case of a single junction. Depending on the stack lateral size,\noscillations may have either the period of half flux quantum per junction\n(wide-stack regime) or one flux quantum per junction (narrow-stack regime). We\nstudy in detail the crossover between these two regimes. Typical size\nseparating the regimes is proportional to magnetic field meaning that the\ncrossover can be driven by the magnetic field. In the narrow-stack regime the\nlattice structure experiences periodic series of phase transitions between\naligned rectangular configuration and triangular configuration. Triangular\nconfigurations in this regime is realized only in narrow regions near\nmagnetic-field values corresponding to integer number of flux quanta per\njunction.\n