High frequency microwave emission from BSCCO intrinsic junctions

We studied the microwave emission properties of very thin mesa structures of high quality Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/ (BSCCO) single crystals grown by the traveling solvent floating zone technique. To increase the anisotropy of crystal, the samples were annealed at 400-600/spl deg/C for 1-20 hrs. The mesa height was 15-45 nm, for which 10-30 resistive hysteresis branches in the I-V characteristics might be expected. The emission power from the stack of the intrinsic junctions was measured by a superheterodyne detection technique at receiving frequencies f/sub rec/=12 GHz, 36 GHz and 47 GHz. For the first time, we observed two kinds of emission modes, one may be explained by microwave emission from phase-locked Josephson junctions, and the other may be caused by the injection of quasiparticle current into the layered intrinsic junction system.