High frequency microwave emission from BSCCO intrinsic junctions

We studied the microwave emission properties of very thin mesa structures o f high quality Bi2Sr2CaCu2O8 (BSCCO) single crystals grown by the traveling solvent floating zone technique. To increase the anisotropy of crystal, th e samples were annealed at 400 - 600 degrees C for 1-20 hrs, The mesa heigh t was 15-35 nm, for which 10-30 resistive hysteresis branches in the I-V ch aracteristics might be expected. The emission power from the stack of the i ntrinsic junctions was measured by a superheterodyne detection technique at receiving frequencies f(rec) = 12 GHz, 36 GHz and 47 GHz, For the first ti me, we observed two kinds of emission modes, one may be explained by microw ave emission from phase-locked Josephson junctions, and the other may be ca used by the injection of quasiparticle current into the layered intrinsic j unction system.