Ground states in artificial spin ice

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

Gilbert, Ian

关键词: Ising model;    statistical mechanics;    micromagnetics;    nanomagnetism;    frustrated magnetism;    artificial spin ice;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/78318/Gilbert_Ian1.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

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.