Effect of Disorder in the Structure of a Ferroelectric Composite Material xPbSe·(1 – x)PbSeO3 on the Smearing of the Phase Transition

Abstract

This paper analyzes the experimental and theoretical studies of the problem of a diffuse phase transition (PTC) in a composite material xPbSe⋅(1 – x)PbSeO3, in which x varies from 0 to 1. The decrease in stability in the virtual cubic phase of lead selenide (PbSe) is achieved by oxidizing it with atmospheric oxygen and forming a ferroelectric disordered monoclinic phase of lead selenite (PbSeO3). The mechanism of lead selenide oxidation by air oxygen is studied by X-ray diffractometry, optical reflection in the infrared region of the spectrum, X-ray emission analysis (the chemical shift method), nuclear magnetic resonance, studies of AC and DC conductivity, differential scanning calorimetry, and other methods. The reason for the smearing of the phase transition in the xPbSe⋅(1 – x)PbSeO3 composite, in which x varies from 0 to 1, is analyzed based on the previously obtained experimental results of its detection.