Admasu, Alemayehu Solomon. Synthesis of complex oxides,optimized for the study of novel structural and magnetic properties. Retrieved from https://doi.org/doi:10.7282/t3-yx3d-d444
DescriptionIn this dissertation, we synthesize and characterize complex materials using old and new techniques and uncover new candidates for novel physical phenomena. From an experimental standpoint, in chapter 1, we will briefly introduce general methods of bulk crystal growth and then delve into recent advances in specific methods and complex materials including the Laser-diode heated floating zone (L-FZ) and use of chemical vapor transport and flux methods for the growth of large single crystals with physically interesting properties (e.g spin-ice) as well as less studied class of materials. Then in chapter 2, we review on the origin and interesting properties of the stuffed tridymite structure, with the specific case of the incongruently melting stuffed tridymite BaCoSiO4, which will motivate the study to reveal its structural properties following the first single crystal growth by L-FZ. In chapter 3, discuss the magnetic properties and low temperature neutron powder diffraction resolved magnetic structure enabling to further investigate possible magnetism induced anti-polar state. In chapter 4, we report on the first single crystal growth and magnetic ground state characterization of a previously less studied class of complex oxides RE2SrAl2O7 for RE = Nd,Sm,Gd,Tb,Dy and RE2SrSc2O7 for RE = Gd,Tb. In particular, we investigate the structure and magnetism in Tb2SrAl2O7 for new magnetic phenomena. In chapter 5, we conclude this dissertation with a summary of the results and future research directions, which will open access into the synthesis and characterization of previously unstudied class of materials such as refractory oxides.