Structure-Property Relationships in Novel Materials. Part 1: Frustrated Magnetism and Deintercalation of Honeycomb Oxides. Part 2: Electron-Precise Gold Intermetallics

Abstract

This thesis is a study of the structure-property relationships of novel materials, broken into two major parts. The first part, “Part I: Frustrated Magnetism and Deintercalation of Honeycomb Oxides” explores new, layered nickel oxides and their properties, specifically the synthesis, structure, magnetism, and applications of the Na3Ni2BiO6-NaNi2BiO6-NaNi2BiO6●1.7H2O system. These phases are of interest to the solid-state and physics communities because they display frustrated magnetism on a hexagonal lattice. Chapter 3 explores the chemistry and physics of Na3Ni2BiO6; Chapter 4 then discusses its chemical deintercalation and subsequent hydration to form the NaNi2BiO6-NaNi2BiO6●1.7H2O system. These phases are examples of sought-after spin-1/2 systems on a hexagonal lattice.

The second part of this thesis, “Part II: Electron-Precise Gold Intermetallics” explores novel, electron-precise intermetallics in the Lanthanide-gold-pnictide ternary system. The chemistry of gold-containing solids has not been well-studied despite gold’s unusual physics, motivating the study. There are three new families discussed herein. The first, found in Chapter 7, is of the type LnAuSb (Ln = Lanthanide) which are new Dirac semimetals. The work illustrates a chemical design principle that can be used to predict new Dirac Semimetals, which is important given that the field of topological materials is rapidly growing. Chapter 8 discusses materials of the type LnAuBi2, which are layered intermetallics with a high degree of magnetic anisotropy. Finally, Chapter 9 explores new phases of the form Ln3Au3Bi4. These materials are semiconductors with high Seebeck coefficients at room temperature, indicating their potential for use as thermoelectric materials.