Magnetism in Quasicrystals: Outlook and Challenges

Alan Goldman

Department of Physics and Astronomy, Iowa State University

Ames Laboratory, U.S. DOE

https://lsu.zoom.us/j/8705147953

The discoveries of a new family of magnetic quasicrystals, exhibiting spin-glass-like behavior, and their closely related crystalline approximants, which manifest long-range magnetic order at low temperature, offer new opportunities for studies of the impact of aperiodicity on magnetic interactions in compounds that have similar local structures. Local-moment-bearing binary quasicrystals represent the compositionally simplest system for the study of magnetic interactions in aperiodic compounds and, therefore, the R-Cd quasicrystal family will play a key role in these studies, offering non-magnetic, Y, Heisenberg-like, Gd, and non-Heisenberg (CEF split) Tb to Tm members, in addition to the structural and compositional simplicity of a binary phase. Here, I will describe our progress in the understanding of magnetism in quasicrystals and their related periodic approximants, including results of x-ray and neutron scattering investigations of both phases, studies of crystal field excitations, and magnetic diffuse scattering from the i-Tb-Cd quasicrystal. We have only really scratched the surface, so I will try to focus on the outstanding issues and challenges that we face as we seek a comprehensive understanding of magnetism in these fascinating compounds.