High field electron magnetic resonance in complex correlated spin systems [Elektronische Ressource] / von Mohammed Yehia Taha Ahmed Elbahrawy

High fleld electron magnetic resonance incomplex correlated spin systemsDissertationzur Erlangung des akademischen GradesDoctor rerum naturalium(Dr. rer. nat.)vorgelegtder Fakult˜at fur˜ Mathematik und Naturwissenschaftender Technischen Universit˜at DresdenvonMaster-PhysikerMohammed Yehia Taha Ahmed ElbahrawyDresden, Juli 2010Gutachter:Prof. Dr. B. Buchner˜Prof. Dr. M. GoiranProf. Dr. H.-H. Klau… AbstractLow dimensional (low-D) strongly correlated spin systems are an important topic incondensed matter physics. The dimension of the system and the spin value play a crucialroleforthenatureofgroundstates. Thereduceddimensionandtheinterplaybetweenspin,orbital and charge degrees of freedom yield a variety of fascinating phenomena like super-conductivity, quantum liquid and spin gap states, chiral phases, etc. Magnetic materialsrealizing these systems are quite often found in transition metal oxides such as cupratesand vanadates. In this thesis, we used the electron spin resonance spectroscopy (ESR) toinvestigate magnetic properties of low dimensional vanadium and copper oxides in whichsmall quantum spins (S = 1=2) are arranged in 1D chains or 2D layers. In particular, weapplied the technique of frequency tunable sub-Terahertz ESR in strong magnetic flelds togain insights into the complex and rich physics of these systems.