abstract
Powders of (1-x)La(Mg1/2Ti1/2)O-3-xSrTiO(3) series have been prepared by a non-conventional chemical route based on the Pechini method. Homogeneous solid solutions allowed the sintering of dense and single-phase ceramics for the full composition range (0 less than or equal to v < 1). Crystal structure of the ceramics was investigated by XRD and several compositional driven structural transformations were observed. The dielectric function of the ceramics was measured at radio, microwave and far infrared (FIR) frequency ranges to help clarifying the relationship between dielectric properties and structure. The FIR data were found to reflect clearly the sequence of structural modifications observed. In order to evaluate the importance of intrinsic mechanisms in the dielectric response at the GHz and MHz ranges, the reflectivity spectra were fit to the Berreman-Unterwald form of dielectric function. The fits showed that the lower frequency dielectric response seems to be dominated by lattice phonons. Microwave permittivity and temperature coefficient of the resonant frequency were found to obey a hyperbolic-type law. (C) 2003 Elsevier Ltd. All rights reserved.
keywords
COMPLEX PEROVSKITES; SYSTEM
subject category
Materials Science
authors
Seabra, MP; Salak, AN; Ferreira, M; Ribeiro, JL; Vieira, LG
our authors
Andrei Salak
Principal Researcher
Maria Paula Seabra
Assistant Professor