The ferroelectric, ferromagnetic, and magnetoelectric properties of (1- x) Pb( Zr0.52Ti0.48)O-3 - xNiFe(1.9)Mn(0.1)O(4) (PZT- NFM) ceramic composites were found to be dependent upon postsinter annealing and aging. It was found on annealing and aging that (i) the size and density of the NFM phase is reduced, (ii) the PZT lattice constants changed from (a=3.8 angstrom, c= 4.07 angstrom) to (a= 4.07 angstrom, c= 4.09 angstrom), (iii) the ferroelectric and ferromagnetic Curie temperatures decreased by 8 and 33 degrees C, respectively, and (iv) the magnetoelectric coefficient increased by 50%. (C) 2007 American Institute of Physics.