Title :
Microwave quality factor improved by ordering of Ba and rare-earth on the tungsten bronze-type Ba6-3xR8+2xTi18 O54 (R=La, Nd and Sm) solid solutions
Author :
Ohsato, H. ; Imaeda, M. ; Takagi, Yutaka ; Komura, Akiyoshi ; Okuda, Takafumi
Author_Institution :
Nagoya Inst. of Technol.
Abstract :
Microwave dielectric properties of the tungsten bronze-type Ba6-3xR8+2xTi18O54 (R=La, Nd and Sm) solid solutions are investigated as a function of the composition x. The quality factor which is the inverse of the dielectric loss changes non-linearly as a function of the composition, though the dielectric constant and the temperature factor of the resonant frequency changes linearly. The distribution of large cations in the rhombic sites and the pentagonal sites in the crystal structure leads to this non-linearity. When the rare earth ions and Ba ions occupy separately the rhombic sites and pentagonal sites, the quality factor is the highest. The internal strain is reduced at x=2/3, which is confirmed from FWHM by X-ray diffraction experiments
Keywords :
X-ray diffraction; barium compounds; crystal structure; dielectric losses; internal stresses; lanthanum compounds; neodymium compounds; permittivity; samarium compounds; solid solutions; Ba6La8Ti18O54; Ba6Nd8Ti18O54; Ba6Sm8Ti18O54; X-ray diffraction; crystal structure; dielectric constant; dielectric loss; internal strain; microwave quality factor; pentagonal sites; resonant frequency temperature factor; rhombic sites; solid solutions; Capacitive sensors; Dielectric constant; Dielectric losses; Neodymium; Q factor; Resonant frequency; Solids; Temperature; Tungsten; X-ray diffraction;
Conference_Titel :
Applications of Ferroelectrics, 1998. ISAF 98. Proceedings of the Eleventh IEEE International Symposium on
Conference_Location :
Montreux
Print_ISBN :
0-7803-4959-8
DOI :
10.1109/ISAF.1998.786743
