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Chiral switching and dynamic barrier reductions in artificial square ice

Authors :
Leo, Naëmi
Pancaldi, Matteo
Koraltan, Sabri
Villalba González, Pedro
Abert, Claas
Vogler, Christoph
Slanovc, Florian
Bruckner, Florian
Heistracher, Paul
Hofhuis, Kevin
Menniti, Matteo
Suess, Dieter
Vavassori, Paolo
Leo, Naëmi
Pancaldi, Matteo
Koraltan, Sabri
Villalba González, Pedro
Abert, Claas
Vogler, Christoph
Slanovc, Florian
Bruckner, Florian
Heistracher, Paul
Hofhuis, Kevin
Menniti, Matteo
Suess, Dieter
Vavassori, Paolo
Publication Year :
2021

Abstract

Collective dynamics in lithographically-defined artificial spin ices offer profound insights into emergent correlations and phase transitions of geometrically-frustrated Ising spin systems. Their temporal and spatial evolution are often simulated using kinetic Monte Carlo (kMC) simulations, which rely on the precise knowledge of the switching barriers to obtain predictive results in agreement with experimental observations. In many cases, however, the barriers are derived from simplified assumptions only, and do not take into account the full physical picture of nanomagnetic switching. Here we describe how the immediate magnetic square- or kagome-ice environment of a nanomagnet reversing via quasi-coherent rotation can induce clockwise and counter-clockwise switching channels with different barrier energies. This energy splitting for chiral reversal channels can be sizeable and, as string-method micromagnetic simulations show, is relevant for artificial spin ice systems made of both exchange- as well as magnetostatically-dominated units. Due to the barrier splitting and further reductions due to non-uniform reversal, transition rates can be exponentially enhanced by several orders of magnitude compared to mean-field predictions, especially in the limit of rare switching events where thermal excitation is less likely. This leads to significantly faster relaxation time scales and modified spatial correlations. Our findings are thus of integral importance to achieve realistic kMC simulations of emergent correlations in artificial spin systems, magnonic crystals, or the evolution of nanomagnetic logic circuits.

Details

Database :
OAIster
Notes :
English
Publication Type :
Electronic Resource
Accession number :
edsoai.on1269458088
Document Type :
Electronic Resource
Full Text :
https://doi.org/10.1088.1367-2630.abe3ad