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Open Access Nano Express

Ferromagnetism in sphalerite and wurtzite CdS nanostructures

Zhaolong Yang, Daqiang Gao, Zhonghua Zhu, Jing Zhang, Zhenhua Shi, Zhipeng Zhang and Desheng Xue*

Author Affiliations

Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, 730000, People’s Republic of China

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Nanoscale Research Letters 2013, 8:17  doi:10.1186/1556-276X-8-17

Published: 7 January 2013

Abstract

Room-temperature ferromagnetism is observed in undoped sphalerite and wurtzite CdS nanostructures which are synthesized by hydrothermal methods. Scanning electron microscopy and transmission electron microscopy results indicate that the sphalerite CdS samples show a spherical-like shape and the wurtzite CdS ones show a flower-like shape, both of which are aggregated by lots of smaller particles. The impurity of the samples has been ruled out by the results of X-ray diffraction, selected-area electron diffraction, and X-ray photoelectron spectroscopy. Magnetization measurements indicate that all the samples exhibit room-temperature ferromagnetism and the saturation magnetization decreases with the increased crystal sizes, revealing that the observed ferromagnetism is defect-related, which is also confirmed by the post-annealing processes. This finding in CdS should be the focus of future electronic and spintronic devices.

Keywords:
CdS nanostructures; Hydrothermal methods; Room-temperature ferromagnetism; Sulfur vacancies