The magnetic properties of ferromagnetic GaMnNAs films grown by plasma-assisted molecular beam epitaxy (p-MBE) have been studied. All samples showed p-type conductivity in the present experiment. The 1.0% nitrogen content samples showed metallic behavior, whereas the 1.5% nitrogen content samples showed insulating behavior. The Curie temperature T-c showed the saturation with the Mn content increasing, and the critical Mn concentration for the saturation depended on the nitrogen content. (c) 2006 Elsevier B.V. All rights reserved.