DocumentCode
1869
Title
Defect-Induced Room-Temperature Ferromagnetism in 
Nanowires Controlled by UV Light Irradiation
Author
Bhaumik, Sudipta ; Sinha, Arun Kumar ; Ray, Samit K. ; Das, Amal K.
Author_Institution
Dept. of Phys. & Meteorol., IIT Kharagpur, Kharagpur, India
Volume
50
Issue
5
fYear
2014
fDate
May-14
Firstpage
1
Lastpage
6
Abstract
Nonferromagnetic SnO2 nanowires show ferromagnetism at room temperature, which is significantly enhanced upon irradiation by ultraviolet (UV) light of wavelength 365 nm. The structural characterizations on as-grown, UV-irradiated, and O2-annealed samples show no measurable difference in X-ray diffraction profiles and field-emission scanning and transmission electron microscopy images. But optical absorption, photoluminescence, and X-ray photoelectron spectroscopy reveal a significant effect of UV irradiation and establish a remarkable enhancement of O vacancies in SnO2 nanowires upon UV light irradiation, which diminishes after annealing in the presence of O2 gas. The as-grown and O2-annealed nanowires show weak ferromagnetism at room temperature, but the UV-irradiated nanowires show strong ferromagnetism. The origin of such ferromagnetism in pure (undoped) SnO2 is attributed to the presence of oxygen vacancies, which is tunable externally using UV irradiation.
Keywords
X-ray diffraction; X-ray photoelectron spectra; absorption coefficients; annealing; coercive force; ferromagnetism; field emission electron microscopy; nanofabrication; nanowires; oxygen; photoluminescence; remanence; scanning electron microscopy; semiconductor growth; semimagnetic semiconductors; tin compounds; ultraviolet radiation effects; O2; SnO2; UV light irradiation; UV-irradiated nanowires; X-ray diffraction profiles; X-ray photoelectron spectroscopy; annealing; defect-induced ferromagnetism; field-emission scanning electron microscopy images; nonferromagnetic nanowires; optical absorption; oxygen vacancies; photoluminescence; structural characterizations; temperature 293 K to 298 K; transmission electron microscopy images; ultraviolet light irradiation; wavelength 365 nm; Annealing; Educational institutions; Lattices; Microscopy; Nanowires; Photonic band gap; Radiation effects; ${rm SnO}_{2}$ nanowires; Oxygen vacancy; SnO2 nanowires; UV light irradiation; oxygen vacancy; room temperature ferromagnetism; room-temperature ferromagnetism;
fLanguage
English
Journal_Title
Magnetics, IEEE Transactions on
Publisher
ieee
ISSN
0018-9464
Type
jour
DOI
10.1109/TMAG.2013.2292575
Filename
6675871
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