Complex conductivity of Y1−xPrxBa2Cu3O7 thin films measured by coherent terahertz spectroscopy

Abstract The complex transmission of Y 1−x Pr x Ba 2 Cu 3 O 7 single crystal thin films has been measured in the range 0.2–1.0 THz using time domain spectroscopy. The complex conductivity is calculated without using a Kramers-Kronig analysis. All of the superconducting samples show a peak in σ 1 ( T ) below T c . The underdoped samples show a deviation from 1/(α + T ) behavior above T c that may be linked with the onset of a spin gap.