FIZIKA A 18 (2009) 4 , 173-184

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SOME CHARACTERISTIC PHYSICAL PROPERTIES OF NICKEL OXIDE POWDER

S. A. GADa, M. BOSHTAa, A. M. ABO EL-SOUDa and M. Z. MOSTAFAb
aSolid State Physics Department, National Research Center, El-Boohoos str., 12311 Dokki, Giza, Egypt
bCeramic, Refractories and Building Materials Department, National Research Center, El-Bohoos st., 11312 Dokki, Giza, Egypt

Received 27 October 2008;    Revised manuscript received 15 April 2009
Accepted 18 November 2009    Online 31 December 2009

Nickel oxide powder was prepared by firing spec pure NiCO3 in air for 6 hours at different firing temperatures ranged from 800C to 1200 C. The crystal structure of all samples is a cubic structural as obtained from XRD study. The diffuse reflectance of different samples of NiO was measured at room temperature in the wavelength range from 200 to 2000 nm. The energy gap of NiO samples was then deduced as well as the position and number of different transitions which were found to be dependent on the firing temperature. The electrical conductivity sm was measured over temperature range from 50C to 320 C and frequency range from 42 Hz to 5 MHz. The conductivity decreases with increasing firing temperature and increases with frequency. The activation energy was calculated and was found to increase with increasing firing temperature. Electron spin resonance (ESR) spectra were recorded at room temperature as first derivatives using an X-band spectrometer with a magnetic field modulation of 100 kHz. The intensity of the ESR-spectra of NiO samples decreases with increasing firing temperature.

PACS numbers: 77.84.Bw, 81.05.Je, 72.80.Jc
UDC 538.911, 538.93, 537.312

Keywords: nickel oxide powder, crystal structure, energy gap, electrical conductivity, electron spin resonance spectra

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