Cumings Tapped for Nature Physics News and Views ColumnDepartment of Materials Science and Engineering assistant professor John Cumings, a recognized expert in the use of artificial spin ice in studies of thermodynamics and crystal lattices, was invited to introduce readers of Nature Physics to the topic in the journal's op-ed News and Views column.
"Frustrated magnets: Artificial ice goes thermal" explains how artificial spin-ice, a metamaterial that simulates the behavior of real ice, is being used to study why water and certain magnetic materials can simultaneously settle into many possible disordered crystal structures, a behavior known as "frustration" that seems to be in conflict with a fundamental law of physics. That law, Third Law of Thermodynamics, states that as the temperature of a pure substance moves toward absolute zero the disorderly behavior of its molecules also approaches zero, and the molecules should line up in a perfectly ordered fashion. Researchers have been using artificial spin ice to study real ice and other "frustrated" materials because it allows for highly controlled simulations under relatively easy conditions—the study of real ice's crystal lattice, by contrast, requires precise maintenance of temperatures below that of liquid nitrogen over extended periods of time.
Cumings introduces and comments on a paper in the same issue, "Thermal ground-state ordering and elementary excitations in artificial magnetic square ice," which presents the design of the first artificial spin ice material that can reach a ground state (that of its least possible energy and complete order) like real materials do, making it a prime candidate for use in studies that seek to discover the ground states of frustrated materials that seem to defy the Third Law of Thermodynamics.
Learn more about artificial spin ice and the mystery of why ice seems to be in conflict with a fundamental law of physics:
"Now That's Cool: Clark School Engineers Out to Thaw the Mysteries of Ice," an introduction to artificial spin ice and metamaterials
Research Spotlight: Artificial Spin Ice, a more technical discussion
"Direct observation of the ice rule in artificial kagome spin ice," a paper published by Cumings and members of his research group in Physical Review B
Published December 22, 2010