Y-Ba-Cu-O grain boundary resistivity above and below the critical temperature

The interface resistance of YBa/sub 2/Cu/sub 3/O/sub 7-(delta)/ grain boundaries has been measured in the range 5-270 K by means of a Wheatstone bridge for 24(degree), 30(degree)and 36(degree)symmetric and 45(degee) degree asymmetric, [001] tilt, thin film grain boundaries. A number of preliminary experiments have demonstrated the validity of the technique employed. Above T/sub c/, the grain boundary resistance decreases as the temperature is increased, and the temperature variation is more pronounced for higher angle boundaries. A number of possibilities for interpreting the data are considered.