Papers by Author: Tatsuro Hotta

Abstract: Structural characterization of various (Li,Na,K)NbO3 solid solutions with different Li contents has been carried out by temperature-variable Raman scattering measurement. It was found that there was no clear thermal hysteresis between orthorhombic-tetragonal phase transition in the heating/cooling processes for (Li,Na,K)NbO3 ceramics with Li content of 6 wt% and above, although a noticeable thermal hysteresis is observed in the Raman spectra and dielectric constant measurement for the other specimens with lower Li contents. It is presumed that the structural change of (Li,Na,K)NbO3 cell tends to become insensibility against temperature as the Li content increases above 6.0 mol%.

Abstract: (Na0.5K0.5)NbO3-LiNbO3 (LNKN) is a lead-free ceramics, reported to show the maximum piezoelectric property when the Li content is 6.0 mol%. The temperature dependence of the spectra was measured for LNKN in the 4.0-8.0 mol% range of Li content by using Raman scattering. The stretching and bending mode of NbO6 octahedron especially changed the form and/or frequency of the spectrum with increasing Li content from 5.0 to 6.0 mol%. The range of this composition is corresponding to the composition with the maximum piezoelectric property.