Cole-Cole analysis and optoelectronic properties, using VEELS, of KNNS ferroelectric ceramics

In this work, Cole-Cole analysis and optoelectronic properties were carried out on K0.1Na0.9Nb0.97Sb0.03O3 (KNNS) ferroelectric ceramics with tetragonal phase. Moreover, some evidence of the 180 degrees domains, relating the electronic interband transitions (Jcv) and the Cole-Cole plot obtained from the complex dielectric function constants. Both obtained by Kramers-Kronig analysis. The experimental method enabled monitoring the mate-rials properties of the material between inter-bands transitions and plasmons. Concerning the optical reflection coefficient observed from KNNS, the observed values of reflection coefficients were about 15% for an energy loss of 0 eV and a peak value at about 32% at 5 eV, followed by a second peak equivalent to 18% at 11 eV. The number of effective electrons (neff) participating in the inter-band transitions of the KNNS material is relevant up to 40 eV. These results suggest that KNNS could be a material to enable terahertz waveguide, enabling a new generation of high-speed communications devices.