Magnetic energy landscape exploration of a classical Heisenberg Hamiltonian

by Prof. Hugo Bocquet (PSI)

Tuesday 18 Oct 2022, 11:00 → 12:00 Europe/Zurich

WHGA/121

In this talk, I will outline my PhD project and the work done so far. Experimentsconducted at PSI investigating the thermal magnetic switching properties of nano-sizedparticles (Fe, Co and Ni) reveal a broad spectrum of fluctuation timescales for nominallythe same particle size and shape. This suggests internal structure plays an importantrole in the thermal stability of the measured magnetic states and motivates the goalof my thesis, which is, to study how lattice defect structure can influence magnetism.The approach taken will be within the framework of a classical magnetic Hamiltonian.After discussing these experimental results in detail, the talk will mainly focus on thecentral activity of my first year, which is how can one systematically explore such classicalmagnetic energy landscapes, finding their potential energy minima and the saddle pointsthat separate them. The developed numerical method will be presented in detail and anumber of case studies will be given. In the last part of my talk, I will discuss how onemight model, within the framework of a classical Heisenberg Hamiltonian, the thermalmagnetic switching properties of an experimentally realistic nano-particle.