Dielectric, pyroelectric and piezoelectric properties in the (1 − x)(0.1BaTiO3–0.9NaNbO3)–xLiNbO3 system

New lead free piezoceramics with the given compositions (1 − x)(0.1BaTiO3–0.9NaNbO3)–xLiNbO3(0.01 ≤ x ≤ 0.125) were prepared by solid–state reaction technique. XRD patterns revealed a single perovskite-structured phase only for 0.01 ≤ x < 0.05. The dielectric, pyroelectric and piezoelectric responses were investigated for compositions with x = 0.01 and 0.02. For both compositions, ɛ’r exhibited a sharp peak with no frequency dependence (classical ferroelectrics). Losses displayed a strong dispersion at low frequencies in the paraelectric phase which was attributed to Li ionic conductivity in these compositions. The spontaneous polarization was found to be 35 and ≈22 μC cm−2 for x = 0.01 and 0.02 respectively. The transverse piezoelectric coefficient d31 measured for x = 0.01 reached value of 37 pC/N at room temperature while the planar coupling factor was about 0.23.

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