Tran , Dang Thanh and Le , Van Hong and Nguyen , Xuan Phuc (2008) Grain-Size Effect on the Dielectric Properties of La1.5Sr0.5NiO4 Nano-Particle Materials. JOURNAL OF THE KOREAN PHYSICAL SOCIETY .
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We have manufactured ceramic samples of La1.5Sr0.5NiO4 and studied their dielectric properties. The samples were prepared by using a reactive mechanical milling technique on D8000-Spex combined with an annealing at a temperature in the range of 700 degrees C - 1000 degrees C. The crystalline structure and the sample's purity were checked by means of X-ray diffraction (XRD) on a SIEMENS D5000 spectrograph. The obtained XRD patterns confirmed that all the samples belonged to the F4K2Ni perovskite layer tetragonal structure with a space group of I4/mmm (139). The grain size of a ceramic sample was estimated based on the Field-emission scanning electron microscopy (FE-SEM) images and was calculated by using the Warren-Averbach method based on the Full Width at Half Maximum (FWHM) of the XRD lines. The results obtained by using the two methods were quite the same. The mean grain size (< D >) of the samples varied from 16.2 nm to 95 nm with the annealing temperature. Dielectric constant (epsilon) of all the samples was estimated from the capacitance measurement at different temperatures in the frequency range of 1 kHz - 13 MHz. The estimated epsilon of all the samples was about 10(5) over the whole frequency range up to 1 MHz. The temperature and the frequency dependences epsilon(f,T), the dielectric constant, were observed and are discussed for all the samples.
|Subjects:||Physical Science > Nanophysics|
Material Science > Nanostructured materials
Material Science > Nanochemistry
|Deposited On:||22 Feb 2010 13:41|
|Last Modified:||22 Mar 2010 15:49|
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