Critical current density under magnetic fields has been improved by the introduction of artificial pinning centers. Nanorods in REBa2Cu3Oy films are significantly effective as c-axis-correlated pinning centers. However, nanorods sometimes tilt from the c-axis direction of superconducting films. To understand the mechanism of nanorod tilting. ErBa2Cu3Oy films containing Ba(Nb0.5Er0.5)O-3 (BNO) nanorods were deposited on a SrTiO3 single crystal with a vicinal surface. Microstructures of the nanorods were examined by transmission electron microscopy (TEM). As a result, it was found that BNO nanorods grew diagonally from steps of the substrate surface in cross-sectional TEM images. The mechanism of the diagonal growth of nanorods can be explained by the segregation coefficient. (C) 2010 Elsevier B.V. All rights reserved.