Room-Temperature Ferromagnetism in Cu Doped GaN Nanowires

• Published in: Nano letters Vol. 7; no. 11; pp. 3366 - 3371
• Main Authors: Seong, Han-Kyu, Kim, Jae-Young, Kim, Ju-Jin, Lee, Seung-Cheol, Kim, So-Ra, Kim, Ungkil, Park, Tae-Eon, Choi, Heon-Jin
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.11.2007
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Copper - chemistry; Cross-disciplinary physics: materials science; rheology; Crystallization; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals; Exact sciences and technology; Gallium - chemistry; Ions; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetics; Materials science; Metal Nanoparticles - chemistry; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanotechnology - methods; Nanowires; Photons; Physics; Scattering, Radiation; Semiconductors; Small particles and nanoscale materials; Studies of specific magnetic materials; Temperature; X-Ray Diffraction; Gallium; Curie point; Doping; Ferromagnetic materials; Magnetic moments; Indium additions; XRD; Gallium nitride; X-ray scattering; Monocrystals; Electronic structure; Anomalous scattering; Ambient temperature; Magnetic circular dichroism; Nanowires; Copper; Bonding; Nanostructured materials; III-V semiconductors
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl0716552

We report magnetism in Cu doped single-crystalline GaN nanowires. The typical diameter and the length of the Ga1 - x Cu x N 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 μB/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 - x Cu x N system is a room-temperature ferromagnetic semiconductor.