Ground states in artificial spin ice

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Gilbert, Ian

Contributors dc:contributor

• Schiffer, Peter E
• Cooper, Lance
• Dahmen, Karin A.
• Abbamonte, Peter M.

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

Statement dc:rights

• Copyright 2015 Ian J. Gilbert

Handle dc:identifier

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

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/78318