Narrowing of band gap and low-temperature spin glass behavior of FeNi co-doped ZnO nanowires

¹  Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University Beijing 100084, China
²  State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Science Beijing 100083, China
³  State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, School of Physics, Peking University - Beijing 100871, China

Corresponding authors: javedsaggu73@yahoo.com rhyu@tsinghua.edu.cn

Received: 26 March 2009
Accepted: 17 August 2009

Abstract

This letter reports on the Raman, optical and magnetic properties of FeNi co-doped ZnO nanowires prepared via a soft chemical solution method. The microstructural investigations show that the NiFe co-dopants are substituted into wurtzite ZnO nanostructure without forming any secondary phase. The co-doped nanowires show a remarkable reduction of 34 nm (267.9 meV) in the optical band gap, while suppression in the deep-level defect transition in visible luminescence. Furthermore, these nanowires exhibit ferromagnetism and an interesting low-temperature spin glass behavior, which may arise due to the presence of disorder and strong interactions of frustrated spin moments of Ni and Fe co-dopants on the ZnO lattice sites.