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-/spl delta// grain boundaries has been measured in the range 5-270 K by means of a Wheatstone bridge for 24/spl deg/, 30/spl deg/ and 36/spl deg/ symmetric and 45/spl deg/ 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.