Ground states in artificial spin ice

Gilbert, Ian

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https://hdl.handle.net/2142/78318 Copy

Description

Title

Ground states in artificial spin ice

Author(s)

Gilbert, Ian

Issue Date

2015-02-27

Director of Research (if dissertation) or Advisor (if thesis)

Schiffer, Peter E

Doctoral Committee Chair(s)

Cooper, Lance

Committee Member(s)

• Dahmen, Karin A.
• Abbamonte, Peter M.

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Ising model
• statistical mechanics
• micromagnetics
• nanomagnetism
• frustrated magnetism
• artificial spin ice

Abstract

Artificial spin ice is a class of arrays of interacting ferromagnetic nanoislands that are used to experimentally model Ising spin systems. It has been successfully used to understand the behavior of frustrated spin systems, particularly the class of magnetic pyrochlore oxides known as spin ice. Here I describe a series of experimental studies that further extend the usefulness of artificial spin ice. First, I outline a thermal annealing technique developed to place artificial spin ice samples into their ground state, which previously-used techniques such as ac demagnetization were unable to do. Second, the shakti lattice, a new lattice geometry that better mimics the behavior of real spin ice, is described. Third, a series of experiments using artificial spin ice to explore memory effects in hysteretic systems is detailed. Finally, I describe real-time photoemission electron microscopy measurements of thermal fluctuations of the nanoisland magnetic moments in another new lattice geometry. All these investigations illustrate the utility of artificial spin ice in bridging the gap between experimental studies of natural materials and theoretical and numerical work.

Graduation Semester

2015-5

Type of Resource

text

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http://hdl.handle.net/2142/78318

Copyright and License Information

Copyright 2015 Ian J. Gilbert

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