Phys.org December 17, 2024
When the geometrical size of a nanomagnetic system is constricted to the limiting domain wall length scale, the competing energetics between anisotropy, exchange, and dipolar interactions can cause emergent kinetics due to quasiparticle relaxation, like bulk magnets of atomic origin. A team of researchers in the US (Columbia University, Oak Ridge National Laboratory) conducted an experimental and theoretical study to support that constricted nanomagnets, made of antiferromagnetic and paramagnetic neodymium thin film with honeycomb motif, revealed fast kinetic events at picosecond timescales due to the relaxation of topological quasiparticles that persisted to low temperature in the absence of any external stimuli. This discovery was especially important because paramagnets or antiferromagnets have no net magnetization. The kinetics in neodymium nanostructures were quantitatively like that found in ferromagnetic counterparts and only varied with the thickness of the specimen. According to the researchers, this suggested that universal, topological quasiparticle-mediated dynamic behavior could be prevalent in nanoscopic magnets, irrespective of the nature of the underlying magnetic material… read more. Open Access TECHNICAL ARTICLEÂ
Quasiparticle-mediated dynamics in AFM and FM honeycomb lattices of constricted nanoscopic elements. Credit: Physical Review Research, 6, 043144, 15 November, 2024