On Monday April 14th 2025, we have the pleasure to welcome in SPINTEC Carenza Cronshaw from University of York. She will give us a seminar at 14:00 entitled :
Ultrafast dynamics of antiferromagnets
Place : IRIG/SPINTEC, room 447 CEA Building 10.05 (presential access to the conference room at CEA in Grenoble requires an entry authorization. Request it before April 03th at admin.spintec@cea.fr)
Abstract : Antiferromagnetic spintronics offers the potential of ultrafast, high-performing, energy efficient magnetic devices. However, the interaction of antiferromagnets and electrical currents and ultrafast optical pulses is extremely complex. There arises a need for comprehensive understanding of these dynamics in order to efficiently apply antiferromagnets within magnetic devices. Here we present atomistic simulations of ultrafast heating of the ferromagnetic, L10, L12 and phases of IrMn to understand how varying the number of sub lattices changes the dynamic behaviour of the material. Understanding the dynamic behaviour of
-IrMn3, we then show single-shot ultrafast switching of coupled IrMn/CoGd, including the granular structure of the
-IrMn3 film. We demonstrate that the value and sign of the exchange bias field can be controlled through the application of a single femtosecond laser pulse in the IrMn/CoGd bilayers. Our results show a complex switching process for IrMn that is probabilistic in nature, with each laser pulse completely demagnetising the IrMn, preventing the switching displaying accumulative effects. We find the exchange bias is set by the exchange originating from the Co sublattice rather than an externally applied field, setting in picoseconds, and providing the fastest and most energy efficient method of setting the exchange bias. The high ordering temperature and thermal stability of the IrMn/CoGd bilayers make it highly suited for applications within ultrafast spintronic devices. This work used the ARCHER2 UK National Supercomputing Service https://www.archer2.ac.uk
Biography: Carenza is a third year PhD student at the University of York, having completed her undergraduate degree in Physics in 2022. During her undergraduate studies she was awarded the O.S. Heavens Prize for the highest degree performance and for her masters dissertation “Atomistic simulations of spin-orbit torque switching of Pt/MnPt bilayers” she was awarded the Goodwin Prize best final year project. Her research focuses on computational modelling the dynamics of antiferromagnets, focusing on applications within green computing.
