2026-04-17T02:55:17Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1296022025-12-04T20:46:01Zcom_2072_1057col_2072_478822col_2072_478917

00925njm 22002777a 4500 dc Batlle Gelabert, Xavier author Iglesias, Òscar author Labarta, Amílcar author 2019-03-05T09:11:54Z 2019-03-05T09:11:54Z 2009-03-20 2019-03-05T09:11:55Z In the present work, we investigate the magnetic properties of ferrimagnetic and noninteracting maghemite gamm-Fe2O3 hollow nanoparticles obtained by the Kirkendall effect. From the experimental characterization of their magnetic behavior, we find that polycrystalline hollow maghemite nanoparticles exhibit low blocked to superparamagnetic transition temperatures, small magnetic moments, significant coercivities and irreversibility fields, and no magnetic saturation on external magnetic fields up to 5 T. These results are interpreted in terms of the microstructural parameters characterizing the maghemite shells by means of atomistic Monte Carlo simulations of an individual spherical shell. The model comprises strongly interacting crystallographic domains arranged in a spherical shell with random orientations and anisotropy axis. The Monte Carlo simulation allows discernment between the influence of the polycrystalline structure and its hollow geometry, while revealing the magnetic domain arrangement in the different temperature regimes. Nanopartícules Ferromagnetisme Mètode de Montecarlo Nanoparticles Ferromagnetism Monte Carlo method Magnetic domains and surface effects in hollow maghemite nanoparticles