Structural determination and microwave properties of (x)Re(Co1/2Ti1/2)O3-(1-x)CaTiO3 (Re = La and Nd) solid solutions

• Published in: Journal of the European Ceramic Society Vol. 26; no. 6; pp. 875 - 882
• Main Authors: CAIRNS, D. L, REANEY, I. M, OTTEN, N, IDDLES, D, PRICE, T
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 2006
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric loss and relaxation; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electrotechnical and electronic ceramics; Exact sciences and technology; Permittivity (dielectric function); Physics; Technical ceramics; Cobalt oxide; Scanning electron microscopy; Electrical properties; CaTiO3; Dielectric properties; Binary system; Microwave dielectrics; Calcium Titanates; Microwave; Composition effect; Experimental study; Solid solution; X ray diffraction; Oxide ceramics; Structure composition relationship; Transmission electron microscopy; Solid state reaction; La(Co,Ti)O3; Cobalt Rhenium Titanium Oxides Mixed; Manufacturing; Titanium oxide; Rhenium oxide; Electroceramics; Crystalline structure
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2004.11.024

Solid solutions of (x)Re(Co1/2Ti1/2)O3-(1-x)CaTiO3 (Re = La and Nd, abbreviated to xLCT and xNCT, respectively) where x = 0, 0.25, 0.5, 0.75 and 1 were fabricated by solid state synthesis. Samples were examined using XRD, SEM, TEM and their dielectric properties were measured at microwave (MW) frequencies. Formation of single phase solid solutions were confirmed by XRD and the measured lattice parameters varied linearly from LCT and NCT to CT. XRD and TEM confirmed both in-phase and antiphase rotations of O-octahedra consistent with an a-a-c+ tilt system across the entire solid solution series. Electron diffraction revealed that LCT and NCT have reflections associated with B-site cation ordering which is absent for x up to 0.75. MW dielectric measurements showed that LCT and NCT were highly insulating with microwave quality factor (Qf) values of 39000 and 34000, respectively. Compositions anticipated to have a zero temperature coefficient of resonant frequency are 0.48LCT-CT and 0.52NCT-CT, with dielectric constant and Qf values of 45 and about 5000 and 43 and about 4000, respectively. 17 refs.