Dislocation-Driven Nucleation Type Switching Across Repeated Ultrafast Magnetostructural Phase Transition

Fuente: arXiv
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Autores principales: Hajduček, Jan, Andrieux, Antoine, Arregi, Jon Ander, Tichý, Martin, Cattaneo, Paolo, Ferrari, Beatrice, Carbone, Fabrizio, Uhlíř, Vojtěch, LaGrange, Thomas
Formato: Preprint
Publicado: 2025
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author Hajduček, Jan
Andrieux, Antoine
Arregi, Jon Ander
Tichý, Martin
Cattaneo, Paolo
Ferrari, Beatrice
Carbone, Fabrizio
Uhlíř, Vojtěch
LaGrange, Thomas
author_facet Hajduček, Jan
Andrieux, Antoine
Arregi, Jon Ander
Tichý, Martin
Cattaneo, Paolo
Ferrari, Beatrice
Carbone, Fabrizio
Uhlíř, Vojtěch
LaGrange, Thomas
contents Controlling magnetic order on ultrafast timescales, driven by spintronic and recording applications, is one of the main directions of current research in magnetism. Despite major advances in understanding the temporal evolution of magnetic order upon its emergence or quenching, experimental demonstration of the local link between microstructure and dynamic nucleation is missing. Here, taking advantage of the high structural and magnetic resolution of in situ transmission electron microscopy, we observe that cumulative laser irradiation significantly alters the nucleation pathway of the first-order antiferromagnetic to ferromagnetic phase transition of FeRh thin films, causing the transition to switch from homogeneous to heterogeneous nucleation. This leads to a decrease of 20 K in transition temperature and the emergence of sub-micron magnetic vortices as preferential nucleation motifs. These vortices are pinned in the film by underlying dislocation networks. We observe that the dislocation networks are formed and rearranged upon repeated crossing of the phase transition using femtosecond and picosecond laser pulses. Our results establish a direct link between defect formation, nucleation energetics, and the microscopic morphology of the nucleated ferromagnetic phase, with broad implications for ultrafast stroboscopic experiments and defect-mediated phase transitions in functional materials.
format Preprint
id arxiv_https___arxiv_org_abs_2507_18364
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dislocation-Driven Nucleation Type Switching Across Repeated Ultrafast Magnetostructural Phase Transition
Hajduček, Jan
Andrieux, Antoine
Arregi, Jon Ander
Tichý, Martin
Cattaneo, Paolo
Ferrari, Beatrice
Carbone, Fabrizio
Uhlíř, Vojtěch
LaGrange, Thomas
Mesoscale and Nanoscale Physics
Materials Science
Controlling magnetic order on ultrafast timescales, driven by spintronic and recording applications, is one of the main directions of current research in magnetism. Despite major advances in understanding the temporal evolution of magnetic order upon its emergence or quenching, experimental demonstration of the local link between microstructure and dynamic nucleation is missing. Here, taking advantage of the high structural and magnetic resolution of in situ transmission electron microscopy, we observe that cumulative laser irradiation significantly alters the nucleation pathway of the first-order antiferromagnetic to ferromagnetic phase transition of FeRh thin films, causing the transition to switch from homogeneous to heterogeneous nucleation. This leads to a decrease of 20 K in transition temperature and the emergence of sub-micron magnetic vortices as preferential nucleation motifs. These vortices are pinned in the film by underlying dislocation networks. We observe that the dislocation networks are formed and rearranged upon repeated crossing of the phase transition using femtosecond and picosecond laser pulses. Our results establish a direct link between defect formation, nucleation energetics, and the microscopic morphology of the nucleated ferromagnetic phase, with broad implications for ultrafast stroboscopic experiments and defect-mediated phase transitions in functional materials.
title Dislocation-Driven Nucleation Type Switching Across Repeated Ultrafast Magnetostructural Phase Transition
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2507.18364