Development of Scientific Fundamentals for the Conversion of a Virtual Binary Lead Selenide Ferroelectric into a Real Ferroelectric of Lead Selenite for Physico-Chemical Sensors

Abstract

The scientific basis for the production of a new composite material (1-x)PbSexPbSeO₃, where x=0-1, by oxidation with oxygen at temperatures of 500-550 °C and oxidation times of 0.5-4 h from the initial phase of PbSe in the form of powder, film or compact material, having a ferroelectric phase transition in disordered crystals is developed. On the X-ray spectra of the original PbSe samples oxidized at 500°C (oxidation time of 0.5 h) it has been found that the PbSe phase reflexes are predominately present, including the X-ray spectra of the original PbSe samples oxidized at 500 °C (oxidation time of 4 h) - PbSeO₃ monoclinic phase reflexes. For all other PbSe oxygen-oxidized samples at temperatures of 500-550 °C and within the time range of 0.5-4 h, X-ray spectra show the simultaneous presence of X-ray reflexes of both phases with the trend of increasing the PbSeO₃ phase as the oxidation time increases. Temperature measurements of the DC resistance of the PbSe samples revealed an abnormal change in electrical resistance at the initial oxidation stage for both the film and the compact material, and further oxidation contributed to the capsulation of PbSe grains by the dielectric casing PbSeO₃ and the gradual increase in the resistance of the material.