Far infrared reflectance of sintered nickel manganite samples for negative temperature coefficient thermistors

Journal Article · Tue Aug 07 00:00:00 EDT 2007 · Materials Research Bulletin

DOI:https://doi.org/10.1016/j.materresbull.2006.11.005· OSTI ID:21000686

Nikolic, M V ^[1]; Paraskevopoulos, K M ^[2]; Aleksic, O S ^[1]; Zorba, T T ^[2]; Savic, S M ^[3]; Blagojevic, V D ^[4]; Lukovic, D T ^[3]; Nikolic, P M ^[3]

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1. Center for Multidisciplinary Studies of the University of Belgrade, Kneza Viseslava 1, 11000 Belgrade (Serbia)
2. Department of Physics-Solid State Section, Aristotle University, Thessaloniki (Greece)
3. Institute of Technical Sciences of SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia)
4. Faculty of Electronic Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade (Serbia)

Single phase complex spinel (Mn, Ni, Co, Fe){sub 3}O{sub 4} samples were sintered at 1050, 1200 and 1300 deg. C for 30 min and at 1200 deg. C for 120 min. Morphological changes of the obtained samples with the sintering temperature and time were analyzed by X-ray diffraction and scanning electron microscope (SEM). Room temperature far infrared reflectivity spectra for all samples were measured in the frequency range between 50 and 1200 cm{sup -1}. The obtained spectra for all samples showed the presence of the same oscillators, but their intensities increased with the sintering temperature and time in correlation with the increase in sample density and microstructure changes during sintering. The measured spectra were numerically analyzed using the Kramers-Kroenig method and the four-parameter model of coupled oscillators. Optical modes were calculated for six observed ionic oscillators belonging to the spinel structure of (Mn, Ni, Co, Fe){sub 3}O{sub 4} of which four were strong and two were weak.

• OSTI ID: 21000686
• Journal Information: Materials Research Bulletin, Vol. 42, Issue 8; Other Information: DOI: 10.1016/j.materresbull.2006.11.005; PII: S0025-5408(06)00435-1; Copyright (c) 2006 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
ABSORPTION SPECTROSCOPY
CERAMICS
COBALT OXIDES
INFRARED SPECTRA
MANGANESE OXIDES
MICROSTRUCTURE
MORPHOLOGICAL CHANGES
NICKEL
NICKEL OXIDES
OPTICAL MODES
OSCILLATORS
REFLECTIVITY
SCANNING ELECTRON MICROSCOPY
SINTERING
SPINELS
TEMPERATURE COEFFICIENT
THERMISTORS
X-RAY DIFFRACTION