A novel approach to fabricating high Qm PZT

SAW devices are being investigated for TV-IF filters and mobile telephone applications. Additions of MnO₂ to PZT can result in materials with zero temperature coefficients and low propagation losses. The available Q_m´s of PZT materials however, can limit their usefulness in energy-critical applications. In this work, a novel approach to improving the performance of PZT was attempted. The effect of both a dopant atom (Mn) and electron dopant pyrochlore phase, Sr₂Sb₂O₇, were examined. MnO₂ was added at 0.1, 0.3, and 0.5 wt% levels while the pyrochlore was added at the 5 mol% level. It was postulated that the pyrochlore phase might limit grain growth and reduce domain motion, thus increasing Q_m. It was further postulated that compositions with both the pyrochlore and Mn doping should yield even greater Q_m values. Properties of interest, k_p, Q_m, e, and loss, were measured by the resonance method. In summary, Mn doping was effective in improving properties. Pyrochlore additions did reduce grain size; however, the properties were degraded