Lecture by Honorary Doctor Steven T. Bramwell

  • Date: –14:15
  • Location: Ångströmlaboratoriet, Lägerhyddsvägen 1 Polhemsalen, Å10134
  • Lecturer: Steven T. Bramwell, Department of Physics & Astronomy and London Centre for Nanotechnology University College London, UK
  • Organiser: Department of Physics and Astronomy
  • Contact person: Björgvin Hjörvarsson
  • Föreläsning

Public lecture by Professor Steven T. Bramwell, appointed honorary doctor at the Faculty of Science and Technology 2019, with the title Puzzles and paradigms in a model magnet.

Abstract

Puzzles and paradigms in a model magnet
The magnetic system "spin ice" has proved to be a rich source of unconventional problems in condensed matter. This talk will be divided into three parts. In the first part I will briefly review the basic physics of spin ice, describing how it affords both a model "vertex" system with Pauling entropy and a model lattice Coulomb gas composed of emergent magnetic "monopoles". In the second part I will offer solutions to two recent puzzles: first how in ultra-thin film spin ice, the Pauling entropy of spin ice vanishes without an apparent phase transition, and second, how in bulk spin ice neutron scattering indicates the existence of a subtle "harmonic phase" that coexists with the monopole Coulomb gas. Finally I will describe the broad relevance of these results to many physical systems.

 

British physicist and chemist Steven T. Bramwell is Professor of Physics at University College London and head of research at the London Centre for Nanotechnology. He was one of the researchers who experimentally discovered what is known as spin ice. Bramwell has also demonstrated that two-dimensional magnets have a critical exponent that can be defined theoretically, and he has coined the term ‘magnetricity’ for the magnetic equivalence of electric current. Bramwell has been named by The Times as one of the 100 leading scientists in the United Kingdom. He has had a long-standing collaboration with researchers at the Ångström Laboratory through seminars, lectures, exchanges and joint publications and has actively contributed to the development of the faculty’s research in the field of magnetism.