Date of Award

5-2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Physics

Major Professor

Haidong Zhou

Committee Members

Christian D. Batista, Jian Liu, David G. Mandrus

Abstract

The foundation of experimental condensed matter physics is comprised of two material processes, synthesis and characterization. For most measurements, single crystal samples are preferred as they allow spatially dependent information to be obtained. On the other hand, polycrystalline samples are also critical as they reveal bulk properties of the material and are generally much easier to produce. Material characterization then relies on accurately measuring a material's physical, electrical, and magnetic properties using a variety of different techniques.In this dissertation, we focus on triangular lattice antiferromagnets (TLAFs) which have been studied because of their great potential to exhibit various intriguing magnetic properties related to strong geometrical frustration. Recent studies of TLAFs mainly explore four central themes: quantum spin liquid (QSL) states, exotic disordered states, the coplanar 120 degree state and the related field induced spin state transitions, and multiferroicity. Accordingly, we have investigated two materials which fall into these categories. The first is the magnetodielectric material RCr(BO3)2 (R = Y and Ho), and the second is a group of Mo-cluster compounds including the quantum spin liquid candidate Li2In1-xScxMo3O8 and the ferromagnets (Mg,Zn)ScMo3O8. Both materials have been investigated using x-ray diffraction, powder neutron diffraction, ac and dc susceptibility, and specific heat capacity measurements as well as other complementary techniques. A discussion of these results as well as potential future experiments are included.

Comments

Portions of this text have been published in Physical Review B, R. Sinclair, et al., Phys. Rev. B 95, 174410 (2017), and arxiv, A. Akbari-Sharbaf, R. Sinclair, et al., arXiv:1709.01904v2 (2017).

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