We have studied frequency and temperature dependences of complex sheet conductance of ultrathin (1-3 unit cell (UC) thick) YBa2Cu3O7-x films using a radio frequency (1-20, 100-1000 MHz) sheet impedance and a microwave (30 GHz) loss measurements. We found the activated temperature dependence of the vortex diffusion constant and scaling behaviour of the universal ratio TKTBDC/Lk-1(TKTB) for 1UC, 2UC and 3UC YBCO films, in close agreement with theoretical prediction for vortex-antivortex unbinding transition.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering