Nano-clusters structure and magnetic properties of high fluence Mn+ ion-implanted GaN

The n-type GaN film was grown on sapphire substrate by metal organic chemical vapour deposition (MOCVD). Mn+ ions of 75 keV with the fluence of 8 x 10(17)/cm(2) were implanted in the GaN at 350 degrees C. The implanted sample was annealed at 850 degrees C to recrystallize the sample and to remove implantation damage. We investigated the structural and magnetic properties of Mn+ ion-implanted GaN by using Rutherford back-scattering (RBS), high resolution transmission electron microscopy (HRTEM) and superconducting quantum interference device (SQUID). RBS results showed the Mn+ ions were concentrated near the surface. HRTEM results showed nano-clusters structure in the sample. The temperature dependence of magnetization taken in zero-field-cooling and field-cooling conditions with the block temperature was 267 K and hysteresis loops which exhibited a transformation from ferromagnetism to superparamagnetism showed the features of magnetic nano-clusters system. And it could be explained the magnetic property of this film originated from Mn-rich clusters. (C) 2008 Elsevier B.V. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000257721300031&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Instruments & InstrumentationNuclear Science & TechnologyPhysics, Atomic, Molecular & ChemicalPhysics, NuclearSCI(E)EICPCI-S(ISTP)1