КАТИОННЫЕ ЗАМЕЩЕНИЯ В СЛОИСТОЙ ПЕРОВСКИТОПОДОБНОЙ СТРУКТУРЕ Bi4Ti3O12: ОБЗОР

Multiferroics have become an urgent research topic in recent years, due to exhibiting both magnetic and electrical ordering within their structure. Сompounds having multiferroic properties at room temperature are of particular interest. One of the possible ways to develop new multiferroic materials is to start with a series of well-proven ferroelectrics and create additional functionality by partial substitution some ions with other suitable ions. Aurivillius phases are the promising materials for this purpose. These compounds are well known for their excellent ferroelectric properties and have great potential for adapting specific properties by changing both the ionic composition and the number of layers. Layered bismuth titanate Bi4Ti3O12 was chosen as a starting object for the modification of properties. The purpose of this article is to consider various literature sources, determine the effect of cation substitutions on the structure of the Aurivillius phase Bi4Ti3O12, and determine the prospects for the further research.В последние годы мультиферроики стали актуальной темой исследований, поскольку в их структуре возможно сосуществование магнитного и электрического упорядочения. Соединения, обладающие свойствами мультиферроиков при комнатной температуре, представляют особый интерес. Один из возможных способов разработки новых мультиферроиков - взять за основу серию хорошо зарекомендовавших себя сегнетоэлектриков и создать дополнительную функциональность путем частичного замещения одних ионов другими, удовлетворяющими параметрам структуры. Фазы Ауривиллиуса являются перспективными материалами для этой цели. Данные соединения известны своими превосходными сегнетоэлектрическими свойствами и имеют большой потенциал для адаптации конкретных свойств путем изменения как катионного состава, так и количества слоев. В качестве исходного объекта для модификации свойств был выбран слоистый титанат висмута Bi4Ti3O12. Цель данной статьи - исходя из информации, представленной в различных литературных источниках, определить влияние катионных замещений на структуру фазы Ауривиллиуса Bi4Ti3O12, а также выявить перспективы дальнейших исследований

PROPERTIES OF LAYERED Bi5FeTi3O15: REVIEW

Nowadays the study of Aurivillius phases is associated with a wide area of their application in modern equipment. In recent years, these materials are being actively studied in order to create multiferroics. The compound Bi5FeTi3O15 is among the commonly investigated types of Aurivillius phases. However, its properties can be improved. Several factors influence the properties of this Aurivillius phase. The most important of them are listed further. Firstly, substitutions of Bi (III) or Ti (IV) ions in the structure of Bi5FeTi3O15 significantly affect the phase formation, electrical and physical characteristics of ceramics, as well as their thermal stability and Curie temperature. Secondly, the type of synthesis and annealing is also plays a key role in formation of pure phases. Therefore, the aim of this article is to review various literature sources and to reveal consistent patterns in changing properties of Bi5FeTi3O15-based substances and determine the possible objects for the further study

ЯЗЫК ПРОГРАММИРОВАНИЯ PYTHON В РЕШЕНИИ ЗАДАЧ ПО ХИМИИ

The Python programming language has recently acquired popularity due to its wide range of application, as well as its short and simple syntax. Python applications are not limited to web development, machine learning, and data analysis. This article contains the implementation of idea how to use Python to improve the process of composing and solving tasks in chemistry. The programs take into account only the mathematical part of the solution and can be further applied to a wide range of tasks. This approach is intended to simplify the learning process. Thus, students have more tasks to practice their skills while teachers spend less time writing and checking these tasks.Язык программирования Python в последнее время приобрел большую популярность благодаря обширным возможностям использования, а также краткости и простоте синтаксиса. Область применения Python не ограничивается только сферами веб-разработки, машинного обучения и анализа данных. В данной статье рассмотрен вариант использования Python для оптимизации процесса составления и решения задач по химии. Программы учитывают только математический аппарат решения и могут быть в дальнейшем применены к широкому спектру задач. Предложенный подход призван упростить процесс обучения. Таким образом, у студентов будет больше задач, чтобы отработать навыки, а преподаватели будут тратить меньше времени на составление заданий и их проверку

Approach to the methodology for assessing and typologizing excursion objects within the framework of the experience economy concept (on the example of castles in Kaliningrad region)

Currently, there are many approaches to assessing the competitiveness of tourist sites. However, these approaches mainly consider individual factors, such as the availability of a tourist facility, its safety, content, marketing and many others. In this study, the authors drew attention not to individual factors, but to the final result of the activities of tourist facilities, the competitiveness of which is ensured by the formation of impressions after visiting them. Within the framework of the concept “Economy of impressions”, a methodology for assessing the tourist attractiveness of excursion objects is proposed, an approach to the typology of objects is presented in order to develop an effective development strategy and determine the prospects for their use for tourism purposes. Approbation of the methodology for assessing and typologizing excursion objects was carried out on the example of castle structures in the Kaliningrad region

ФАЗООБРАЗОВАНИЕ И СВОЙСТВА ТВЁРДЫХ РАСТВОРОВ НА ОСНОВЕ СЛОИСТОГО ТИТАНАТА ФЕРРИТА ВИСМУТА, СОДЕРЖАЩИХ КАТИОНЫ Nb(V)

Исследованы фазообразование и физико-химические свойства твёрдых растворов Bi5Fe1+yTi3-2yNbyO15 с y = 0.0 - 1.0 и ∆y = 0.2, полученных с использованием муфельного и микроволнового способов термообработки в ходе синтеза. Установлено, что в области гомогенности 0.0 < y < 0.4 полученные фазы характеризуются ромбическим типом симметрии элементарной ячейки. Выявлено, что увеличение содержания катионов Nb(V) в составе полученных фаз приводит к возрастанию объёма элементарной ячейки и понижению температуры сегнетоэлектрического фазового перехода

Properties of lanthanide containing Aurivillius phases Ln2Bi3FeTi3O15 (Ln = La, Pr, Nd, Sm, Gd)

The phase formation in the series Ln2Bi3FeTi3O15 (Ln = La, Pr, Nd, Sm, Gd) was studied. It was found that the layered perovskite structure was formed after annealing at 1000 °C. Further increase in the synthesis temperature to 1100 °C did not affect the phase composition, excluding Gd-containing sample, where perovskite structure was partially destroyed to form the pyrochlore phase based on Bi2Ti2O7. Reversible anomalies obtained by differential thermal analysis indicate the phase transitions with a change in the crystal lattice symmetry in case of a perovskite-like phase and a transition of the order-disorder type in case of a pyrochlore structure. © 2022 Taylor & Francis Group, LLC

Effects of Substitutions of Titanium(IV) Ions by Iron(III) and Niobium(V) Ions on Phase Formation in Lanthanide-Containing Systems Comprising Layered Bismuth Titanate Ferrite

Abstract: Phase formation in the series of Bi3Nd2Fe1 + yTi3 – 2yNbyO15 and Bi3Tb2Fe1 + yTi3 – 2yNbyO15 (y = 0.0–0.6 and Δy = 0.2) samples is studied. When Bi3Nd2Fe1 + yTi3 – 2yNbyO15 solid solutions (ss) are doped with niobium(V) ions, the formation of Bi3Nd2FeTi3O15 layered perovskite, a member of the Aurivillius phase family of general formula Am – 1Bi2BmO3m + 3 (m = 4), is not dominant in samples where y ≥ 0.2. Bi4Ti3O12 (m = 3) and NdFeO3 phases are formed in the course of phase interaction under the chosen conditions. With higher niobium(V) amounts, a Bi2Ti2O7-base pyrochlore ss phase is formed in the Bi3Tb2Fe1 + yTi3 – 2yNbyO15 multicomponent system. Dielectric spectroscopy shows that the phases in samples of both series where y &gt; 0.0 undergo structural alterations associated with magnetic and electric ordering. © 2020, Pleiades Publishing, Ltd