Studium vlastních a nevlastních mikrovlnných dielektrických ztrát pomocí teraherzové a infračervené spektroskopie

Abstract

Nazcv prace: Studium vlastnich a ncvlastm'ch mikrovlnnych diclcktrickych zlrat ponioci leraher/ove a inlVaeervene spcklroskopic Autor: Ondfcj Tkac Katcdra (Ustav): Oddelem dieleklrik, Fy/ikalni ustav, AV CR Vedouci bakalafske prace: RNDr. Slanislav Kamba. C'Sc., Na Slovance 2. Praha 8 e-mail vcdouciho: kTi Abstrakt: V prvni casli prace je strucnc popsana pfislusna tcoric, zejmena sc zde venujeme principu inlraeervene spcktroskopic a lltovacim modelurn, dale vysvelleni pojmii vlastni a ncvlastni dielcktrickc /traty a pojcdnavamc lake o diclektrikach a fcroeleklrikach. Pomoci Fouricrovy infraccrvenc spcktroskopic jsmc mcfili infraccrvcna speklra pri pokojovc Icplole v rozsahu 30 - 3000 cm"1. Spektra jsmc iltovali a vyslcdnou komplcxni permitivitu jsmc cxtrapolovali do mikrovlnnc ohlasti. To nam umo/.nilo odhadnout podil nevlaslnich dielckirickych /tral na celkovych mikrovlnnych zlralach. U kcramickcho Sry.^Ph^CciTiiiO.if, (.v =0 az 9) jsmc studovali vliv obsahu olova na diclektricke vlaslnosli. Zjistili jsmc, /c nahrada slroncia olovcm /pusobujc vzrust pcrmilivity a/ na nckolik lisic a vynucujc leroelcklricky prechod pro x>2. U perovskilu Ca7n].3Nh23-\VxO3 (.v=0 az 0,01) jsmc /koumali vliv obsahu vanadu na diclektricke vlaslnosli, /ejniena na kocllcicnl rcsonancnf Irckvcnce r/ . Dale jsmc studovali vliv...

Title: Study ol"proper and improper microwave dielectric tosses by means of tcrahcrz and infrared speetroseopy Author: Ondfej Tkac Department: Department of Dielectrics. Institute of Physics, Academy of Sciences of C/ech Republic Supervisor: RNDr. Slanislav Kamba.C'Sc.. Na Slovance 2. Prague 8 Supervisor's e-mail adress: kambawT/u.c/ Abstract: In the llrst part of this thesis there is described relevant theory, especially we pay our attention to the principles of infrared speetroseopy and fitting models, then to the explanation of the terms proper and improper dielectric losses and we also discuss dielectrics and ferroelectrics. By means of Fourier transform infrared speetroseopy we measured infrared spectra at room temperature in the range of 30 - 3000 em"1. We lilted the spectra and then we extrapolated the final complex permit!vity into the microwave range. This enabled us to estimate the proportion of improper dielectric losses on total microwave losses. By the ceramic SiVxPlxCeVfinO-^ (.\0 to 9) we studied the impact of amount of lead on dielectric properties. We found out that the substitution of strontium with lead causes the increase of permitivity up lo several thousands and forces ferroelectric transition for x>2. With perovskitc Ca/n, jNb^ :,-xVx(.)1 (.v=0 to 0,01) we examined the inlluence of...