Magnetic and structural properties of Co, Cr, V ion-implanted GaN

We report on the magnetic and structural properties of epitaxial metal organic chemical vapor deposition grown p-GaN:Mg/Al2O3 implanted with Co, Cr, and V ions at varying high doses at 350 °C. Magnetic and structural properties were investigated after a short anneal at 700 °C to remove implantation damage. Magnetic properties determined from superconducting quantum interference device magnetometer measurements indicate ferromagnetic-like ordering for Co and Cr doped samples up to 320 K, while V doped samples show paramagnetic behavior for all temperatures considered. For all samples studied, structural characterization techniques such as x-ray diffraction, high-resolution cross-sectional transmission electron microscopy, and selected area diffraction pattern, indicate no second phases that may contribute to the magnetic properties measured. Transport measurements (resistivity as a function of temperature) reveal all samples to show insulating-like behavior.