Microscopic origin of exchange bias in core/shell nanoparticles

We report the results of Monte Carlo simulations with the aim to clarify the microscopic origin of exchange bias in the magnetization hysteresis loops of a model of individual core/shell nanoparticles. Increase of the exchange coupling across the core/shell interface leads to an enhancement of excha...

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Detalhes bibliográficos
Autores: Iglesias, Òscar, Batlle Gelabert, Xavier, Labarta, Amílcar
Tipo de documento: artigo
Estado:Versão publicada
Data de publicação:2005
País:España
Recursos:Universidad de Barcelona
Repositório:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/10919
Acesso em linha:https://hdl.handle.net/2445/10919
Access Level:Acceso aberto
Palavra-chave:Propietats magnètiques
Termodinàmica
Mètode de Montecarlo
Física estadística
Magnetic properties
Thermodynamics
Monte Carlo method
Statistical physics
Descrição
Resumo:We report the results of Monte Carlo simulations with the aim to clarify the microscopic origin of exchange bias in the magnetization hysteresis loops of a model of individual core/shell nanoparticles. Increase of the exchange coupling across the core/shell interface leads to an enhancement of exchange bias and to an increasing asymmetry between the two branches of the loops which is due to different reversal mechanisms. A detailed study of the magnetic order of the interfacial spins shows compelling evidence that the existence of a net magnetization due to uncompensated spins at the shell interface is responsible for both phenomena and allows to quantify the loop shifts directly in terms of microscopic parameters with striking agreement with the macroscopic observed values.