| Abstract [eng] |
This dissertation explores the applications of the pulsed laser deposition (PLD) method and broadband dielectric spectroscopy to study thin films and bulk materials of some complex perovskite materials such as PbZr₀.₂Ti₀.₈O₃, 0.8(Na₀.₅Bi₀.₅TiO₃)-0.2(BaTiO₃), ZrSnSe₃, Nb-doped and undoped BiFeO₃–BaTiO₃ (BF–BT), and PbHf₀.₉₂Sn₀.₀₈O₃ (PHS) crystal. The dissertation analyzes how different PLD parameters (such as fluence, deposition temperature, ambient pressure, etc.) affect the quality and structure of thin films. Broadband dielectric spectroscopy reveals the dynamics of phase transitions and the dielectric response of different ferroelectric materials at various temperatures. The obtained results show that in BF–BT ceramics, the relaxor-type dielectric dispersion dominates, with frequency-dependent permittivity peaks and thermally induced transitions between ordered and disordered states. In PbHf₀.₉₂Sn₀.₀₈O₃ crystals, the dielectric dispersion maximum shifts towards higher frequencies (to the GHz range) as it approaches the Curie temperature. A very high residual polarization (93 μC/cm²) was obtained in the PbZr₀.₂Ti₀.₈O₃ thin layer, exceeding even the value of the bulk material, which is due to the stresses that have arisen between the layer and the substrate. |
