In this thesis I present the synthesis and characterization of materials exhibiting frustrated magnetism. In Chapter 1 I describe magnetic frustration and some of the magnetic states that can arise from it followed by the background on iridates and platinates with honeycomb structures and rare earth pyrochlores.
In Chapter 3 I discuss my work on the synthesis and properties of ternary sodium iridates with formulas NaxM2/3Ir1/3O 2 and NaxM1/3Ir2/3O2 (M = Mn, Fe, Co, Ni, Cu, Zn). The ternary iridates are based on the honeycomb compound Na2IrO3 but show more disorder in the honeycomb layer than the parent. The six new compounds are all spin glasses but show distinct magnetic properties from one another.
In Chapter 4 I continue my work on honeycombs by exploring new ternary sodium platinates. These three new compounds with formulas Na3MPt 2O6+x (M = Mg, Cu, Zn) are structurally very similar to the iridates discussed in Chapter 2 but have non-magnetic Pt4+ in place of magnetic Ir4+. The Mg and Zn variants are non-magnetic while the Cu variant is paramagnetic at 2 K.
Chapter 5 is a synchrotron X-ray diffraction study of the magnetically frustrated rare earth pyrochlores Ho2Ti2O7, Er2Ti2O7 and Yb2Ti2O 7. Previous neutron scattering studies have shown reflections that are forbidden by the assigned space group Fd-3m, therefore high intensity, high resolution X-ray diffraction data was collected to determine if the reflections are present. Slight variations in sample stoichiometry were studied to account for possible sample variation. The forbidden reflections are absent from the X-ray diffraction patterns, providing strong evidence that the extra reflections in neutron scattering experiments are not structural in origin.
|Advisor:||Cava, Robert J.|
|Commitee:||Bocarsly, Andrew, Selloni, Annabella, Sturm, James C.|
|School Location:||United States -- New Jersey|
|Source:||DAI-B 76/11(E), Dissertation Abstracts International|
|Subjects:||Inorganic chemistry, Materials science|
|Keywords:||Frustrated magnetism, Honeycombs, Iridates, Oxides, Platinates, Pyrochlores|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be