Modeling the Effect of Point Defects on the Structure of Perovskites
Many perovskite-structured ceramic materials are known to have useful microwave dielectric properties, with promising applications in mobile telecommunications, an industry which will be worth an estimated $341 billion by 2015. Current mathematical models used to predict the functional properties of specific perovskites are poorly suited to complex or defective structures. In the present study, a solid-state processing method was used to synthesize perovskite ceramics in the system [(Ca,Sr)1-3n/2Lnn]TiO3 (Ln = La or Nd). Single-phase powder samples were produced at 1300ºC and characterized using X-ray diffraction. The resulting products were then uniaxially pressed to form pellets which were sintered at temperatures up to 1600ºC. This work investigates the effect of point defects on the structure of the resultant perovskites. The ultimate goal is to develop a predictive model, based solely on composition and easily-obtainable published reference data, for the effect of point defects on the structure and, by extension, dielectric properties of perovskites.