Defect-induced ferromagnetism in undoped In{sub 2}O{sub 3} nanowires

Journal Article · Mon Dec 15 00:00:00 EST 2014 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2014.09.043· OSTI ID:22420711

Tien, Li-Chia; Hsieh, Yu-Yun

Highlights: • Undoped In{sub 2}O{sub 3} nanowires were synthesized by a thermal evaporation method. • In{sub 2}O{sub 3} nanowires show d{sup 0} ferromagnetism at room temperature. • Large amount of defects were confirmed by PL, UV/vis, and XPS. • Oxygen deficient surfaces and size effect mediating ferromagnetic ordering. - Abstract: We report the observation of intrinsic room-temperature ferromagnetism in undoped In{sub 2}O{sub 3} nanowires synthesized by a thermal evaporation method. The as-grown sample was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), temperature-dependent photoluminescence (PL), Ultraviolet–visible spectroscopy (UV/vis), X-ray photoelectron spectroscopy (XPS), and superconducting quantum interference device (SQUID). Structural characterizations show that the as-grown sample is single crystal cubic bixbyite structure with 80–100 nm in diameter and 2–4 μm long. Both PL and UV/vis results reveal that the sample exhibits large amount of oxygen vacancies and indium vacancies (V{sub O} and V{sub In}). XPS results indicate that the In{sub 2}O{sub 3} nanowires are significantly oxygen deficient and non-stoichiometric at surface. Experimentally measured magnetic hysteresis curves for undoped In{sub 2}O{sub 3} nanowires clearly display ferromagnetic behavior at room temperature. We believe the ferromagnetism of undoped In{sub 2}O{sub 3} nanowires is ascribed to the large surface area and intrinsic defects mediating the ferromagnetic ordering.

• OSTI ID: 22420711
• Journal Information: Materials Research Bulletin, Vol. 60; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
EVAPORATION
FERROMAGNETISM
FIELD EMISSION
INDIUM OXIDES
MONOCRYSTALS
NANOWIRES
OPTICAL PROPERTIES
PHOTOLUMINESCENCE
SCANNING ELECTRON MICROSCOPY
SQUID DEVICES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TRANSMISSION ELECTRON MICROSCOPY
ULTRAVIOLET RADIATION
VACANCIES
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY