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Sodium niobate (NaNbO3) is the end member of several alkaline niobate-based solid solutions, which represent an important group of environment-friendly lead-free piezoceramics. Even though alkaline niobates are of considerable technological importance, problems in obtaining high densities and a fine-grained microstructure are still reported and not much is known about the …

The main purpose of this thesis is to describe the inhomogeneous phase of a layered system. The phase is the result of the competition between attractive interactions and the long range Coulomb repulsive force (LRCF). In order to achieve this, two different strategies are applied. The first is within the …

The thesis presents experimental studies of colloidal interactions and novel colloidal structures in confined nematic liquid crystal using optical tweezers. Liquid crystal colloids are a novel class of composite materials with well-controlled periodic structures in the nanometer and micrometer ranges. Moreover, they also posses novel mechanical, optical and rheological properties, …

The stress dependence of the electrical permittivity offers a convenient way of measuring pressure. This effect is suitable for static and quasi-static stress applications, where the conventional method based on the piezoelectric effect becomes inadequate. Although the principle of applying this effect for pressure sensing has been known for almost …

This PhD thesis presents experimental results from the synthesis, crystal structure and microwave dielectric characterization of BaO-rich phases within the BaO-Nb2O5 and BaONb2O5- WO3 system. I was primarily interested in two compounds with unknown crystal structure, i.e., the binary Ba4Nb2O9 and the ternary Ba6Nb2WO14, which lie on a common virtual …