Low frequency dielectric response of Cu0.5Tl0.5Ba2Ca2Cu3-xMxO10-δ (M = Cd, Zn, Ni; x=0, 1.5) superconductors

Novel shift in dielectric loss (tanδ) from the negative to the positive value observed in the frequency region between 800 Hz and 1000 Hz in all Cu0.5Tl0.5Ba2Ca2Cu3-xMxO10-δ (M = Cd, Zn, Ni; 1.5) samples is attributed to be arising from the activation of various interfacial polarizations at different frequencies. An enhanced ac-conductivity jump is observed in pristine, Zn and Ni-doped samples which is altogether absent in Cd-doped samples providing unequivocal evidence of generation of an-harmonic oscillations and their pair breaking effects.