Element specific investigations of the structural and magnetic properties of Gd:GaN

The authors present element specific measurements of the x-ray linear dichroism and the x-ray magnetic circular dichroism (XMCD) on Gd: GaN samples. They can show that the majority of the Gd dopant atoms goes to substitutional Ga sites and that a small XMCD is detectable for Gd. There are significant deviations of the magnetic hysteresis recorded for Gd compared to superconducting quantum interference device measurements. Our measurements show that the magnetic signal from the Gd dopant atom itself is rather small highlighting the role of magnetic contributions of the GaN host crystal. (c) 2007 American Institute of Physics.