We have grown AlN on (Mn,Zn)Fe2O4 substrates by pulsed laser deposition (PLD) and investigated their structural properties using high resolution X-ray diffraction (HRXRD), reflection high energy electron diffraction (RHEED), and atomic force microscopy (AFM). We have observed the transition of the RHEED pattern from sharp streaks into clear spots at the early stage of the film growth, which indicates that the growth mode of AlN changed from the two-dimensional mode to the three-dimensional mode due to the stress buildup. RHEED and XRD observations have revealed that hexagonal AlN (0 0 0 1) grows on (Mn,Zn)Fe2O4 (1 1 1) with the in-plane epitaxial relationship of [1 1 -2 0]AlN//[0 1 -1](Mn,Zn)Fe2O4. The lattice mismatch for this alignment is calculated to be 6%. The FWHM value of the AlN (0 0 0 2) X-ray rocking curve is as low as 77 arcsec, which indicates that the density of the threading screw dislocations in the AlN film is quite low. (C) 2002 Elsevier Science B.V. All rights reserved.