| Abstract [eng] |
Every material has different features, which are necessary to investigate with various techniques. The broadband dielectric spectroscopy is the power tool for investigating various materials. It enables not only detect the dielectric strength and the amount of losses at various frequencies but also the characteristic relaxation time, their distribution and the phase diagram of material. Unique feature combinations occur in multiferroic compounds. Ferroelectric relaxor 0.94PbMg1/3Ta2/3O3 – 0.06PbTiO3 possess interesting features. The aim of investigation of this crystal is to find out more about the ferroelectric relaxor features, particularly about the static permittivity behaviour at higher temperatures. Recently a lot of attention was paid to bismuth ferrite because of its ferroelectric and magnetic characteristics’ coexistence. In order to improve this material properties the part of bismuth is replaced with other rare earth elements. Samarium and dysprosium is one of options for such replacement, by changing the concentration of these elements maybe it is possible to improve the properties. Multiferroic materials with Aurivillius structure are also interesting, particularly materials based on Bi4Ti3O12. To obtain multiferroic material the attempts to dope BIT with rare earth metals with magnetic properties (for example gadolinium) was made. In this work Bi4Ti3O12, Bi4−xGdxTi3O12, Bi1−xRExFeO3 (RE = Sm, Dy) dielectric investigations are presented. Recently TTB materials’ family gets more and more attention. Ba2REFeNb4O15 (RE = La, Pr, Nd, Sm, Eu, Gd) is a great example of diverse TTB properties. In this work Ba2NdFeNb4O15, Ba6-2xNd2xFe1+xNb9-xO30, Ba2NdFeNb4-xTaxO15 dielectric properties and phase diagrams were investigated. |
