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Tailoring Strain Properties of (0.94− x ) Bi 1/2 Na 1/2 TiO 3 –0.06 BaTiO 3 – x K 0.5 Na 0.5 NbO 3 Ferroelectric/Relaxor Composites

2014; Wiley; Volume: 97; Issue: 5 Linguagem: Inglês

10.1111/jace.12783

1551-2916

Claudia Groh, Wook Jo, Jürgen Rödel,

Multiferroics and related materials

A remarkable progress in the quest of lead‐free piezoceramics for actuator applications has been made with the development of incipient piezoceramics featured by giant strains. A drawback, however, is the high electric field required to generate this giant strain. A powerful approach to overcoming this drawback lies in relaxor/ferroelectric (FE) composites comprised such giant strain materials (matrix) and a FE or nonergodic relaxor (seed). In this study, we investigate the effect of K 0.5 Na 0.5 NbO 3 content in the matrix and the volume ratio of seed to matrix using composites of 0.93 Bi 1/2 Na 1/2 TiO 3 –0.07 BaTiO 3 as a seed and (0.94 − x ) Bi 1/2 Na 1/2 TiO 3 –0.06 BaTiO 3 – x K 0.5 Na 0.5 NbO 3 as a matrix. The strain of all matrices, independent of their K 0.5 Na 0.5 NbO 3 content, was found to be enhanced by adding a certain amount of seed. An optimum strain is achieved for the composite comprised of a matrix with x = 0.02 K 0.5 Na 0.5 NbO 3 and 10% seed. By means of a differential analysis on the temperature‐dependent dielectric permittivity, it was shown that the seed phase is still present in the composites despite the naturally expected diffusion process during sintering.