%0 Journal Article
%T Ho2O3 additive effects on BaTiO3 ceramics microstructure and dielectric properties
%A Paunovi£¿ Vesna
%A Miti£¿ Vojislav V.
%A Miljkovi£¿ Miroslav
%A Pavlovi£¿ Vera
%J Science of Sintering
%D 2012
%I International Institute for the Science of Sintering, Beograd
%R 10.2298/sos1202223p
%X Doped BaTiO3-ceramics is very interesting for their application as PTCR resistors, multilayer ceramic capacitors, thermal sensors etc. Ho doped BaTiO3 ceramics, with different Ho2O3 content, ranging from 0.01 to 1.0 wt% Ho, were investigated regarding their microstructural and dielectric characteristics. The samples were prepared by the conventional solid state reaction and sintered at 1320¡ã and 1380¡ãC in an air atmosphere for 4 hours. The grain size and microstructure characteristics for various samples and their phase composition was carried out using a scanning electron microscope (SEM) equipped with EDS system. SEM analysis of Ho/BaTiO3 doped ceramics showed that in samples doped with a rare-earth ions low level, the grain size ranged from 20-30¦Ìm, while with the higher dopant concentration the abnormal grain growth is inhibited and the grain size ranged between 2- 10¦Ìm. Dielectric measurements were carried out as a function of temperature up to 180¡ãC. The low doped samples sintered at 1380¡ãC, display the high value of dielectric permittivity at room temperature, 2400 for 0.01Ho/BaTiO3. A nearly flat permittivity-response was obtained in specimens with higher additive content. Using a Curie-Weiss low and modified Curie-Weiss low the Curie constant (C), Curie temperature (Tc) and a critical exponent of nonlinearity (¦Ã) were calculated. The obtained value of ¦Ã pointed out that the specimens have almost sharp phase transition. [Projekat Ministarstva nauke Republike Srbije, br. 172057: Directed synthesis, structure and properties of multifunctional materials]
%K BaTiO3
%K microstructure
%K sintering
%K additive
%K dielectric properties
%U http://www.doiserbia.nb.rs/img/doi/0350-820X/2012/0350-820X1202223P.pdf