Title :
Microwave Dielectric Properties of Corundum-Structured (Mg4-xMx)(Nb2-yAy)O9 (M=Mn, Co, and Zn, A=Ta and Sb) Ceramics
Author :
Kan, A. ; Ogawa, H.
Author_Institution :
Meijo Univ., Nagoya
Abstract :
The (Mg4 -xMx)(Nb2-yAy)O9 (M=Mn, Co, and Zn, A=Ta and Sb) compound with corundum structure were prepared and the microwave dielectric properties, crystal structure and covalency of cation-oxygen bonds of the compounds were investigated in this study. The global instability index (GII) of (Mg4-xMx)Nb2O9 compounds was higher than that of Mg4(Nb2-yAy)O9 compounds and the GIl values of (Mg4-xMx)Nb2O9 compounds increased with increasing the composition x. From the calculation of cation-oxygen bonds, it was found covalency of M-O bond in the (Mg4-xMx)Nb2O9 compounds decreased, depending on the composition. The dielectric constant of the compounds ranged from 11 to 16 by the M substitutions for Mg, whereas the quality factor (Q f) drastically decreased form 210000 to 5000 GHz. On the other hand, the A substitution for Nb enhanced the increase in the Q f value of the compounds; the highest value was 347000 GHz.
Keywords :
cobalt compounds; crystal structure; magnesium compounds; manganese compounds; niobium compounds; permittivity; zinc compounds; Mg4CoNb2SbO9; Mg4CoNb2TaO9; Mg4MnNb2SbO9; Mg4MnNb2TaO9; Mg4ZnNb2SbO9; Mg4ZnNb2TaO9; cation-oxygen bonds; corundum-structured ceramics; covalency; crystal structure; dielectric constant; global instability index; microwave dielectric properties; Ceramics; Dielectric constant; Dielectric materials; High-K gate dielectrics; Land surface temperature; Microwave theory and techniques; Powders; Q factor; Resonant frequency; Zinc;
Conference_Titel :
Applications of Ferroelectrics, 2007. ISAF 2007. Sixteenth IEEE International Symposium on
Conference_Location :
Nara
Print_ISBN :
978-1-4244-1334-8
Electronic_ISBN :
1099-4734
DOI :
10.1109/ISAF.2007.4393316
