Title :
Crystal structure and dielectric properties of Ca0.85Nd0.1TiO3 - LnAIO3 ceramics
Author :
Kim, Eung S. ; Kang, Dong H. ; Yang, Jun-Mo ; Shin, Hyung S. ; Zahari, Nur I. ; Ohsato, Hitoshi
Author_Institution :
Dept. of Mater. Eng., Kyonggi Univ., Suwon
fDate :
5/1/2008 12:00:00 AM
Abstract :
The microwave dielectric properties of Ca0.85 Nd0.1TiO3-LnAlO3 (Ln = Sm, Gd, Dy, Er) ceramics are investigated in this paper. The structural characteristics of the specimens were evaluated by Rietveld refinement of X- ray diffraction (XRD) patterns and high-resolution transmission electron microscopy (HRTEM). Solid solution limits were dependent on the ionic radius of Ln3+ ions. With the decrease of the ionic radius of the Ln3+ ions, the thermal stability of the resonant frequency decreases. This can be attributed to the increased level of oxygen octahedral distortion caused by the increase in the B-site bond valence in the ABO3 perovskite structure. The dielectric constant (K) and the quality factor (Qf) of the specimens were dependent on the polarizability and grain size, respectively.
Keywords :
X-ray diffraction; calcium compounds; ceramics; crystal structure; dielectric polarisation; dysprosium compounds; erbium compounds; gadolinium compounds; grain size; microwave materials; neodymium compounds; permittivity; samarium compounds; thermal stability; transmission electron microscopy; Ca0.85Nd0.1TiO3-DyAlO3; Ca0.85Nd0.1TiO3-ErAlO3; Ca0.85Nd0.1TiO3-GdAlO3; Ca0.85Nd0.1TiO3-SmAlO3; HRTEM; Rietveld refinement; X-ray diffraction; XRD; ceramics; crystal structure; dielectric constant; grain size; high-resolution transmission electron microscopy; microwave dielectric properties; polarizability; thermal stability; Ceramics; Crystallization; Electric Conductivity; Materials Testing; Membranes, Artificial; Molecular Conformation;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2008.759
