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Title: Magnetic domains and surface effects in hollow maghemite nanoparticles

Abstract

In the present work, we investigate the magnetic properties of ferrimagnetic and non-interacting maghemite 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 arranggement in the different temperataure regimes.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Materials Sciences Division
OSTI Identifier:
963028
Report Number(s):
LBNL-2099E
Journal ID: ISSN 1098-0121; TRN: US200917%%156
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 79; Journal Issue: 9; Related Information: Journal Publication Date: Mar 2009; Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
36; ANISOTROPY; GEOMETRY; KIRKENDALL EFFECT; MAGNETIC FIELDS; MAGNETIC MOMENTS; MAGNETIC PROPERTIES; SATURATION; SIMULATION; TRANSITION TEMPERATURE; hollow maghemite nanoparticles, magnetic domain,

Citation Formats

Cabot, Andreu, Alivisatos, A Paul, Puntes, Victor, Balcells, Lluis, Iglesias, Oscar, and Labarta, Amilcar. Magnetic domains and surface effects in hollow maghemite nanoparticles. United States: N. p., 2008. Web.
Cabot, Andreu, Alivisatos, A Paul, Puntes, Victor, Balcells, Lluis, Iglesias, Oscar, & Labarta, Amilcar. Magnetic domains and surface effects in hollow maghemite nanoparticles. United States.
Cabot, Andreu, Alivisatos, A Paul, Puntes, Victor, Balcells, Lluis, Iglesias, Oscar, and Labarta, Amilcar. Tue . "Magnetic domains and surface effects in hollow maghemite nanoparticles". United States. https://www.osti.gov/servlets/purl/963028.
@article{osti_963028,
title = {Magnetic domains and surface effects in hollow maghemite nanoparticles},
author = {Cabot, Andreu and Alivisatos, A Paul and Puntes, Victor and Balcells, Lluis and Iglesias, Oscar and Labarta, Amilcar},
abstractNote = {In the present work, we investigate the magnetic properties of ferrimagnetic and non-interacting maghemite 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 arranggement in the different temperataure regimes.},
doi = {},
journal = {Physical Review B},
issn = {1098-0121},
number = 9,
volume = 79,
place = {United States},
year = {2008},
month = {9}
}