Josephson plasma in various high-Tc cuprates

Josephson plasma in various high-Tc cuprates with and without magnetic field is studied by using the sphere resonance method. For Bi2Sr2CaCu2I8+δ, the plasma in a zero magnetic field exists at 5 cm-1 for a slightly overdoped sample (Tc = 85 K) and shifts to 11 cm-1 as the doping increases (Tc = 71 K). For SmLa1-xSrxCuO3.95 (T* phase), two peaks appear at 11 and 30 cm-1 in a zero magnetic field, and both peaks shift to lower frequencies as the magnetic field increases. These peaks are identified as the Josephson plasma of the intrinsic Josephson junction at the fluorite-type sm2O2 block layer and the rocksalt-type (La,Sr)2O2-δ block layer, respectively. This indicates that the T* phase can be regarded as the horellipsisS/I/S/Iprime/S/I/S/Iprime/Shorellipsis (horellipsissuperconductor/insulator1/superconductor/insulator2/super conductor horellipsis)-type Josephson junction array