Out-of-Plane Dielectric Behavior of Insulating Bi2Sr2RECu2O8+δ(RE= Dy, Y, and Er)

This report describes the low-frequency dielectric response of lightly doped Bi 2 Sr 2 RE Cu 2 O 8+δ ( RE : rare earth) with various oxygen contents. The out-of-plane dielectric constant ε c ′ exhibits an anomalous temperature dependence that is independent of RE elements, suggesting that the insulating Bi 2 Sr 2 CaCu 2 O 8+δ (Bi2212) systems have a two-dimensional dielectric character at low temperatures. In disordered solids such as RE -substituted Bi2212 compounds, the charge carrier displays a localized character and the forced movement causes a dc current flow. Furthermore, the oxygen dopants act as trapped sites and strongly affect the out-of-plane dielectric properties.