Isotope Effect in YBa2 Cu3 O7 : Measurements for Two Methods of Synthesis.

摘要

We prepared superconducting samples of YBa2 Cu3 ((18) O)/sub 7-x/ and YBa2 Cu3 ( (16) O)/sub 7-x/ by two techniques: (a) burning powder of YBa2 Cu3 in (18) O2 and (16) O2 and (b) crystallizing amorphous powder of YBa2 Cu3 ( (16) O)/sub 7.8/ in flowing (18) O2 and (16) O2 . The percent of (18) O in the YBa2 Cu3 ((18) O)/sub 7-x/ samples was 96.5 at.% for method (a) and 92 at.% for method (b). The YBa2 Cu3 ((16) O)/sub 7-x/ samples had 99.8 at.% (16) O. Susceptibility measurements of the superconducting transition temperature show an oxygen isotope effect of 0.4 K for both methods. (ERA citation 14:022556)