Exceptionally High Dielectric Constant in Ceramic Pr2CuO4


Author to whom correspondence should be addressed. e-mail: psalame@iitb.ac.in


The pristine layered cuprate Pr2CuO4 samples of >95% density were fabricated as thin disks. The samples, analyzed by X-ray diffraction and Scanning electron microscopy, showed clean T′-type phase with Rietveld refined lattice parameters a = = 3.95805(±5) Å and = 12.2262(±5) Å. The measured dielectric properties of the Pr2CuO4 ceramics, in the temperature range −100°C–150°C and frequencies (ν) 0.1 Hz–1 MHz, showed extremely high εr′ > 104 (above −30°C), and dissipation (tan δ = εr′′/εr′) between 0.1 and 5 (for 500 Hz ≤ ν ≤ 1 MHz, and −100 ≤ T ≤ 150°C). The ac conductivity of Pr2CuO4 ceramics ranged between 10−6 and 10−3 Scm−1 for the measured frequencies and temperatures, and showed frequency-dependent double power law behavior akin to a modified Jonscher's power law.