Perspective on RBa2Cu3Ox materials from oxygen deficiency studies

Abstract

We have measured the electrical resistivity, thermoelectric power, magnetic susceptibility, Hall coefficient and upper critical field near T, in EuBazCu30,, where 6.09 <xc 7.0. These data suggest a Mott-Hubbard-like transition near a critical oxygen concentration x,-6.4-6.5. Our results, combined with those reported elsewhere, show a striking similarity between the addition of oxygen to EuBazCu306 and the substitution of divalent atoms M for La in La_,M,CuO.+ We suggest that superconductivity in both systems is associated with the Cu-0 planes and is driven electronically.

Investigation of thermoelectric power with modification of two band model with linear T term for superconductors and thermal conductivity study of Se added YBCO samples

“…In the optimum-doped YBCO materials, S shows the very weak temperature dependence at high temperatures between 200 K and 300 K and increases linearly with decreasing temperature. A maximum peak just before T c is observed and then S drops to zero [17][18][19][20].…”

PhaseTransformations in the High-Tc Superconducting Compounds, Ba2RCu3O7-delta (R = Nd, Sm, Gd, Y, Ho, and Er)

“…Figure 9 shows a typical plot of the rationalized ac susceptibility of Ba 2 RCu 3 O 7− x [ 31 ] as a function of temperature. The annealing temperatures are indicated from 400 °C to 708 °C.…”

A study on the thermoelectric power and thermal conductivity properties of the Y1−xNdxBa2Cu3O7−δ system

“…doi:10.1016/j.jmatprotec.2007.12.078 content, it is found that TEP shows the very weak temperature dependence at high temperatures (T > 200-300 K). TEP increases linearly with decreasing temperature (Forro et al, 1989;Yan et al, 1988;Kwok et al, 1988) which is common TEP behavior in different HT c systems associated with the CuO 2 plane. A maximum peak just before T c is observed which is attributed to the phonon-drag by some researchers.…”