The structural, optical, and magnetic properties of Cu-implanted GaN films have been investigated. No secondary phase was found within the resolution limit of the instrument but the lattice defects such as vacancies were present in the film. Room temperature ferromagnetism was observed with saturation magnetization of 0.3μB/Cu atom. The field-cooled magnetization curves can be well fitted by a Curie-Weiss model and a standard three-dimensional spin-wave model in the low and high temperature ranges, respectively. Our findings indicate that the vacancylike defects should be considered in understanding the observed magnetic properties of the Cu-implanted GaN films.
The paper reports an island nucleation and secondary growth of aligned ZnO : Cu nanorod arrays via thermal vapor phase transport. Results analysis indicates that the secondary segment is epitaxially grown on the ZnO : Cu nanorods with the radius strongly dependent on temperature and the concentration of zinc vapor. The modified characteristic radius (R(c)) model is used to explain the nucleation and secondary growth process. Temperature-dependent photoluminescence spectra indicate that the band gap emission of the secondary growth nanorods is greatly restrained. A controversial 3.31 eV emission (A line) and two different donor-acceptor pair (DAP) recombinations at 3.24 eV and 2.48 eV are observed at 13 K. The A line shows a different behavior from the two DAP emissions during the heat-up process. Intrinsic room temperature ferromagnetism (RTFM) is observed in the secondary growth ZnO : Cu nanorods and it can be explained by oxygen vacancy and copper defects related to bound magnetic polar (BMP) or double exchange mechanism.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.