The structure of BaCu3O4 particles occurring on thin HoBa2Cu3O7 films prepared by MOCVD

The structure of BaCu3O4 phase occurring as particles on the surface of (00 1) RBa2Cu3O7 epitaxial films prepared by metalorganic chemical vapor deposi tion (MOCVD) has been investigated with quantitative electron diffraction a nd HREM. The orthorhombic unit cell is a = 1.097(9) nm, b = 0.554(3) nm, c = 0.394(2) nm with space group Cmmm, the values being in agreement with X-r ay diffraction (XRD) study. The structure consists of alternating Cu3O4 and Ba layers along the c-axis. The compound is stabilised due to the formatio n of low-energy coherent boundaries with RBa2Cu3O7 and/or perovskite substr ate. (C) 1999 Elsevier Science B.V. All rights reserved.