YBa2CU3O7-delta (YBCO) thin films were used as seed films for growing high peritectic temperature (T-P) Nd1+xBa2-xCu3O7-delta (NdBCO) thick films by liquid phase epitaxy. On heating to a temperature above T-p, polycrystalline YBCO grains agglomerate and then partially decompose. The metastable YBCO phase takes the lowest energy configuration, an enlarged size and a shape with an equilibrium curvature, which prohibits them from immediate decomposition and dissolution. As a result, the retained YBCO grains act as heteroeptaxial-seeds for the growing NdBCO grains in the Nd-Ba-Cu-O solution. Yttrium was detected in the NdBCO grains grown in the initial stage by EPMA, strongly supporting a model of the YBCO-seeded NdBCO growth. (C) 2002 Elsevier Science B.V. All rights reserved.