title: Room-temperature ferromagnetism in Cu doped GaN nanowires.
abstract: We report magnetism in Cu doped single-crystalline GaN nanowires. The typical diameter and the length of the Ga1-xCuxN nanowires (x = 0.01, 0.024) are 10-100 nm and tens of micrometers, respectively. The saturation magnetic moments are measured to be higher than 0.86 microB/Cu at 300 K, and the Curie temperatures are far above room temperature. Anomalous X-ray scattering and X-ray diffraction measurement make it clear that Cu atoms substitute the Ga sites, and they largely take part in the wurtzite network of host GaN. X-ray absorption and X-ray magnetic circular dichroism spectra at Cu L(2,3) edges show that doped Cu has local magnetic moment and the electronic configuration of it is mainly 3d9 but mixed with a small portion of trivalent component. It seems that the ionocovalent bonding nature of Cu 3d orbital with surrounding semiconductor medium makes Cu atom a mixed electron configuration and local magnetic moments. These outcomes suggest that the Ga1-xCuxN system is a room-temperature ferromagnetic semiconductor.
authors: Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea.
authors: Han-Kyu
authors: HK
authors: Seong
authors: Jae-Young
authors: JY
authors: Kim
authors: Ju-Jin
authors: JJ
authors: Kim
authors: Seung-Cheol
authors: SC
authors: Lee
authors: So-Ra
authors: SR
authors: Kim
authors: Ungkil
authors: U
authors: Kim
authors: Tae-Eon
authors: TE
authors: Park
authors: Heon-Jin
authors: HJ
authors: Choi
mesh_terms: D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D005708:Gallium / Q000737:chemistry*; D007477:Ions; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires; D017785:Photons; D012542:Scattering, Radiation; D012666:Semiconductors; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D007477:Ions; C473348:gallium nitride; D003300:Copper; D005708:Gallium