EDDY-CURRENT DETERMINATION OF THE ELECTRICAL CONDUCTIVITY-TEMPERATURERELATION OF CD1-XZNXTE ALLOYS

A multifrequency eddy current sensor has been installed in a vertical Bridgman furnace and used to measure the electrical conductivity of Cd 1-xZnxTe alloys (for x = 0, 0.045 and 0.08) as a function of temperatu re during heating and cooling through the melting transition. The cond uctivity of the x = 0.0 and 0.08 samples increased exponentially with temperature up to the melting point. A 4-6 fold increase of conductivi ty accompanied melting, sufficient for the proposed eddy current sensi ng of liquid-solid interfaces in this materials system. Above the melt ing point, the liquid phase conductivity again exponentially increased with temperature. The x = 0.045 sample exhibited similar behavior exc ept in a similar to 30 degrees C interval immediately below the meltin g/solidification transition on heating and cooling. In this temperatur e interval, an ''anomalous'' decrease in conductivity with an increase in temperature was repeatedly observed. Zn has been found to depress the liquid conductivity while that of the solid (near its melting poin t) exhibited a weak maximum in conductivity at x = 0.045. These observ ations raise the possibility of eddy current monitoring of melt compos ition and segregation/homogenization behaviors during post-solidificat ion annealing.