On August 27th, we will resume the MAGNET section seminars.
At this seminar, we will hear a presentation from Institute Laue-Langevin’s Instrument Scientist Andrew Wildes, titled : “The magnetic Hamiltonians for the layered transition metal-PS antiferromagnets: successes and failures’’ (abstract below). The seminar takes place in Building 311, Room 001, and you can also join us via Zoom:
https://dtudk.zoom.us/j/63529891436?pwd=H5AzLorSb6QiHGC1so00XBx8RrQNLo.1
Abstract
The magnetic Hamiltonians for the layered transition metal-PS antiferromagnets: successes and failures
The TM-PS (TM = Mn, Fe, Co, Ni) family of compounds are layered van der Waals magnets. They have been extensively studied in the past but are now the subject of renewed interest as they are intrinsically magnetic and, like graphite, can be delaminated down to monolayer thicknesses. The compounds are isostructural, with the transition metals forming a honeycomb lattice in the quasi-two-dimensional planes, but they show remarkably different magnetic behaviour. Ordered magnetic structures, magnetic anisotropies and exchange constants, and magnetic critical properties vary considerably with the transition metal, essentially a result of removing electrons one at a time from a half-filled d shell. The differences could be understood if appropriate magnetic Hamiltonians could be determined. Knowledge of representative Hamiltonians is also essential information for the suitability of these compounds in device applications. Experiments to test the magnetic Hamiltonians for the TM-PS compounds will be summarised, with particular emphasis on neutron inelastic scattering, and an opinion on the outstanding problems to be solved in determining appropriate Hamiltonians will be expressed.
