EFFECT OF STRESS ALONG THE AB PLANE ON THE JC AND TC OF YBA2CU3O7 THIN-FILMS

We studied the influence of elastic stress along the ab plane (sigma-ab) on the critical current density (J(c)) and transition temperature (T(c)) of epitaxial c-axis-oriented YBa2CU307 thin films. We observed reversible and reproducible increases (with compression) and decreases (with extension) of J(c) and T(c) from their equilibrium values. By comparing dT(c)/d-sigma-ab = 0.045-0.050 K/kbar with the results of hydrostatic-pressure and thermodynamic experiments reported in the literature, we conclude that pressure-induced changes in the ab plane completely account for the changes in T(c) (within our experimental uncertainty). We also show that the mismatch strain between film and substrate does not substantially affect the change in T(c) caused by the external stress.