SUPERCONDUCTING AND NORMAL-STATE PROPERTIES OF BI2SR2CACU2-XGEXOY

The effect of Ge substitution for Cu on the lattice parameters and the temperature dependences of the magnetic moment and electrical resisti vity of Bi2Sr2CaCu2-xGexOy (0 less-than-or-equal-to x less-than-or-equ al-to 0.7) has been investigated. The a parameter is almost constant o ver the whole range of x while the c parameter decreases with increasi ng Ge concentration. The carrier concentration decreases with Ge dopin g with a corresponding suppression of the transition temperature. Incr ease in disorder within the system with increasing Ge concentration le ads to a semiconductor-like behaviour in the x = 0.7 sample. Conductio n in this sample is governed by a three-dimensional variable-range hop ping.