In situ detection of radiation and heat balance in large Bi2212 mesas

Hot-spot formation in stacks of intrinsic Josephson junctions in Bi2Sr2CaCu2O8

“…In this section we address hot spot formation in 3D. The goal is to quantitatively compare our experimental observations with the numerical simulations, using the same code [63] as in [47,49]. Similarly, we also include various electrically and thermally conducting and insulating layers that are in contact with our BSCCO mesas.…”

“…Recently, Yurgens et al have simulated the thermal heating and the temperature distribution in BSCCO IJJ mesas [47,49], using a 3D finite-element software [63]. In this pioneering work the electrical and thermal properties of the various current carrying and insulating layers were taken into account.…”

“…However, the occurring phenomena need further study. For example, the IVCs in [47,49] have been calculated using a selfconsistent procedure based on Newton's law of cooling and Ohm's law and do not exhibit the experimentally observed abrupt changes in differential resistance when the hot spot appears. They resemble much less the experimental curves than the ones calculated in [60][61][62].…”

“…It may, however, serve as a zero order approximation towards solving the full problem. In the simulations we derive the electrical current density in the mesa under investigation and thus also the potential difference between top and bottom electrodes, directly generating the IVC for a sample, following [60][61][62] rather than [47,49].…”

Temperature distribution in a stack of intrinsic Josephson junctions with their CuO-plane electrodes oriented perpendicular to supporting substrate

“…The performance of the mesa-on-crystal emitter [6,7] is limited by a severe Joule heating at the high bias current needed to achieve intense radiation. The experiments [8] and simulations [9] have shown that some parts of the mesas can easily be overheated by the current to temperatures even above the superconducting critical temperature T c . A stand-alone mesa (without the pedestal of single crystal) soldered to a heatsinking metal support would be less prone to Joule heating, and such experiments are under way.…”