USE OF TRICRYSTAL JUNCTIONS TO PROBE THE PAIRING STATE SYMMETRY OF YBA2CU3O7-DELTA

We propose a new method of probing superconducting pairing state symmetry, using tricrystal devices analogous to s- d corner junctions. Two central peaks are observed in the field-modulated critical currents of frustrated YBa2Cu3O 7- tricrystal junctions operating in the short junction limit, consistent with dx2-y2 pairing symmetry, while a single peak is observed for unfrustrated tricrystal devices. A single peak is also observed for frustrated tricrystal junctions operating in the long junction limit, and it is shown theoretically that s- and d-wave superconductors behave the same in this limit. © 1995 The American Physical Society.