Speaker: J. Kane Shenton
Time: November 28, 2019 :: 2:00PM - 3:00PM
Muon spin spectroscopy (µSR), a technique in which spin-polarised positive muons are implanted into a material, has been successfully used to study a wide range of materials. Interpreting µSR spectra, however, often requires knowledge of the precise muon stopping site(s) in the material. In this talk, I will outline our approach to finding muon stopping sites using density functional theory (DFT). We have recently applied this approach to the prototypical linear magnetoelectric, Cr₂O₃. We find that the positively charged muon occupies several distinct interstitial sites, and displays a rich dynamic behaviour involving local hopping, thermally activated site transitions and the formation of a charge-neutral complex composed of a muon and an electron polaron. Using this work as a case study, I will highlight several challenges to modelling muons in magnetic materials and offer some approaches to overcoming these challenges.
J. Kane Shenton is a postdoctoral researcher in the group of Nicola A. Spaldin at ETH Zurich where he works on the theory and simulation of magnetic and multiferroic materials. Kane has worked closely with the Kiefl group at UBC/TRIUMF/SB-QMI on developing methods to model muons in materials. These methods can aid in the interpretation of µSR spectra and expand our understanding of the doping characteristics of hydrogen defects in magnetic materials. Kane obtained his PhD, on understanding structure-function relationships in bismuth ferrite, from University College London (UCL) in 2018, under the supervision of David R. Bowler and Wei Li Cheah.