iron nitride was formed at the interface of multilayered iron metal/aluminum nitride thin films prepared by rf-sputter deposition. Some magnetization values of the multilayers were larger than that of alpha-Fe. The largest value was 233 emu/g of Fe at room temperature for a [Fe(500 nm)/AlN(500 nm)], film prepared at 100 W. Their thermomagnetic behavior was similar to that of alpha"-Fe16N2 with a giant magnetization. The interface reaction occurred between alpha.-Fe and thermally stable AlN forming metastable magnetic iron nitrides during the rf-sputter deposition without substrate heating. The iron nitride layer is expected to have a nitrogen concentration gradient with a depth from the interface. There was no particular kind of iron nitride. (C) 2004 Elsevier B.V. All rights reserved.