Thermally and field-driven mobility of emergent magnetic charges in square artificial spin ice
Abstract
Designing and constructing model systems that embody the statistical mechanics of frustration is now possible using nanotechnology. We have arranged nanomagnets on a two-dimensional square lattice to form an artificial spin ice, and studied its fractional excitations, emergent magnetic monopoles, and how they respond to a driving field using X-ray magnetic microscopy. We observe a regime in which the monopole drift velocity is linear in field above a critical field for the onset of motion. The temperature dependence of the critical field can be described by introducing an interaction term into the Bean-Livingston model of field-assisted barrier hopping. By analogy with electrical charge drift motion, we define and measure a monopole mobility that is larger both for higher temperatures and stronger interactions between nanomagnets. The mobility in this linear regime is described by a creep model of zero-dimensional charges moving within a network of quasi-one-dimensional objects.
Keywords
Cite
@article{arxiv.1809.07472,
title = {Thermally and field-driven mobility of emergent magnetic charges in square artificial spin ice},
author = {Sophie A. Morley and Jose Maria Porro and Aleš Hrabec and Mark C. Rosamond and Edmund H. Linfield and Gavin Burnell and Mi-Young Im and Peter J. Fischer and Sean Langridge and Christopher H. Marrows},
journal= {arXiv preprint arXiv:1809.07472},
year = {2019}
}
Comments
10 pages, 5 figures