Structural and magnetic properties of Co doped GaN

Structural and magnetic properties of Co doped GaN films grown by molecular beam epitaxy on sapphire(0001) substrates were studied. In the X-ray diffraction measurements and the extended X-ray absorption fine structure analysis, the existence of secondary phase that can be assigned as CoGa was suggested. Magnetic measurements were carried out over the temperature range from 5 to 300 K with the external magnetic field up to 5 Tesla. Clear hysteresis and small step in the magnetization curve suggesting ferromagnetic components were observed in the samples with Co concentration between 0.3 at% and 4.7 at%. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)