Sensitive detection of phase transitions by microwave cavity perturbation method: Application to high-Tc superconductor Bi-Sr-Ca-Cu-O system

Abstract The new device of the Microwave Cavity Perturbation method is shown. By observing the temperature dependence of the cavity resonance frequency and the Q value, one can find the phase transitions from abrupt change of these values. As an example of application of the method, two superconducting phase transitions in high- T c superconductors Bi-Sr-Ca-Cu-O system are shown under magnetic field of zero and 0.8 T.