Effect of M underlayer on the structure, microstructure, magnetic properties of FePt films have been studied (M=Ti, Zr, and Hf). The structural results confirm the extensive ordering of FePt in the bilayer films obtained with annealing at temperature 200 degrees C lower than that at which the single layer film has similar ordering. Microstructure data indicate an obvious grain refinement in the bilayer films. Magnetic force microscopy shows a reduced interaction domain size with M underlayer. We suggest that the intermixing between the FePt and underlayers during the post annealing may lower ordering temperature by stimulating the nucleation of the L1(0) phase, causing refined grain and magnetic domain sizes, leading to remarkable enhancement in permanent magnetic properties at lower T-a. The optimized (BH)(max) of FePt films is greatly enhanced from 9.5 MGOe for single layer to 18.1, 19.8, 20.2 MGOe for Ti-, Zr-, and Hf-underlayered films, respectively. (C) 2014 Elsevier B.V. All rights reserved.