Date of Award

2021-05-01

Degree Name

Master of Science

Department

Physics

Advisor(s)

Harikrishnan Nair

Abstract

The P2-type layered hexagonal compound Na2Ni2TeO6 with Ni2+ on a honeycomb lattice was synthesized by the standard solid-state route. Structural characterization chemical phase purity was confirmed by Rietveld refinement of laboratory and synchrotron data. The crystal structure refines well in the P63/mcm space group. Single crystal growth trials using the self-flux-melt method were conducted with limited success. The magnetic transition temperature pertaining to Ni2+ lattice was confirmed by analysis of specific heat capacity to be . The magnetic susceptibility remains largely unchanged in magnetic field of and external pressure of . There is an almost linear response in isothermal magnetization up to . The nuclear structure studied using high resolution neutron diffraction data confirms the results from refinement of synchrotron data. Four different magnetic structure models were used to quantitatively analyze neutron diffraction data, with the best fitting model consisting of two commiserate propagation vectors and with an additional profile term to account for short-range ordering. The long-range magnetic structure produced by the multi-phase model consist of 2D in-plane (ab) zig-zag ferromagnetic chains and are antiferromagnetically arranged in adjacent chains. Inelastic neutron scattering shows Na2Ni2TeO6 has a spin wave excitation with energy at .

Language

en

Provenance

Recieved from ProQuest

File Size

70 p.

File Format

application/pdf

Rights Holder

Nathan Christopher Episcopo

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