Observation of orthorhombic-tetragonal phase equilibria in YBa sub 2 Cu sub (3-x) Fe sub x O sub (7-delta).
08 February 1988
Recent orthohombic-tetragonal (OT) phase equilibria predicted by Khachaturyan and Morris have been observed experimentally in YBa sub 2 Cu sub (3-x) Fe sub x O sub 7 (0.01 - x - 0. 2) by Mossbauer techniques. The relative proportions of O and T phases are found to be functions of Fe concentration. The T-phase grows from, and coexists with, the O-phase as x increases. A non-zero fraction of T-phase persists down to the smallest values of x. A model is presented to interpret the structural aspects of the O-T transition.