Synthesis and characterisation of La(Co1/2Ti1/2)O3

Single phase, dense La(Co1/2Ti1/2)O3 (LCT) ceramics have been fabricated using conventional solid state synthesis. Samples were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy and their dielectric properties were studied at radio and microwave frequencies. X-ray and electron diffraction conclusively revealed that LCT contained in-phase and antiphase rotations of the O-octahedra, consistent with and a−a−c+ tilt system in the Glazer classification. However, XRD indicated that the Co and Ti ions were disordered on the B-site whereas TEM and Raman spectroscopy exhibited reflections and modes which suggested that partial ordering may be present. Moreover, some Raman bands could only be explained by assuming that at least some of the octahedra exhibited a Jahn-Teller distortion. Dielectric measurements indicated that LCT is insulating with low dielectric loss, 0.0024 at 1 MHz and frequency independent relative permittivity, εr=25. A quality factor, Q×fo=38,000 was obtained at microwave frequencies along with a temperature coefficient of the resonant frequency, TCF=−42 MK−1.