Open AccessСегнетоэлектрические фазовые переходы в Sr-=SUB=-9-=/SUB=-Tm(VO_4)-=SUB=-7-=/SUB=- при замещении стронция на кальций и свинец
Author(s) -
О.В. Барышникова,
Д.В. Дейнеко,
М.А. Потаенко,
Ю.Ю. Дихтяр,
С.Ю. Стефанович,
В.А. Морозов,
Б.И. Лазоряк
Publication year - 2020
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2020.05.49242.06m
Subject(s) - ferroelectricity , isostructural , dielectric , second harmonic generation , phase transition , analytical chemistry (journal) , materials science , phase (matter) , atmospheric temperature range , solid solution , crystallography , chemistry , crystal structure , optics , condensed matter physics , thermodynamics , optoelectronics , laser , physics , organic chemistry , chromatography , metallurgy
By solid-phase synthesis at 1373 K in Sr9-xMexTm (VO4)7 systems the solid solutions with Me = Ca (0≤ x≤2) and Me = Pb (0≤ x≤1) were obtained. Single-phase samples at room temperature are isostructural to the Ca3(VO4)2 ferroelectric (space group (sp.gr.) R3c, Z = 6). Substances are characterized by X-ray phase analysis (XRD), second optical harmonic generation (SHG), and dielectric spectroscopy. The intensity of the SHG signal change depending on the substitution cation and its concentration varies in the range of 30-50 units relative to the quartz standard. A reversible ferroelectric phase transition was found in the temperature range 850–960 K. The transition is accompanied by a sharp maximum in the temperature dependence of the dielectric constant. The absence of a SHG signal above the transition temperature indicates the centrosymmetry of the paraelectric phase.