Magnetic nanoparticles: from the nanostructure to the physical properties

Fuente: arXiv
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Main Authors: Batlle, Xavier, Moya, Carlos, Torroellla, Mariona Escoda, Iglesias, Oscar, Rodriguez, Arantxa Fraile, Labarta, Amilcar
Format: Preprint
Published: 2024
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author Batlle, Xavier
Moya, Carlos
Torroellla, Mariona Escoda
Iglesias, Oscar
Rodriguez, Arantxa Fraile
Labarta, Amilcar
author_facet Batlle, Xavier
Moya, Carlos
Torroellla, Mariona Escoda
Iglesias, Oscar
Rodriguez, Arantxa Fraile
Labarta, Amilcar
contents Some of the synthesis methods and physical properties of iron-oxide based magnetic nanoparticles such as Fe3-xO4 and CoxFe3-xO4 are reviewed because of their interest in health, environmental applications, and ultra-high-density magnetic recording. Unlike high crystalline quality nanoparticles larger than a few nanometers that show bulk-like magnetic and electronic properties, nanostructures with increasing structural defects yield a progressive worsening of their general performance due to frozen magnetic disorder and local breaking of their crystalline symmetry. Thus, it is shown that single-crystal, monophasic nanoparticles do not exhibit significant surface or finite-size effects, such as spin canting, reduced saturation magnetization, high closure magnetic fields, hysteresis-loop shift or dead magnetic layer features which are mostly associated with crystallographic defective systems. Besides, the key role of the nanoparticle coating, surface anisotropy, and inter-particle interactions are discussed. Finally, the results of some single particle techniques -- magnetic force microscopy, X-ray photoemission electron microscopy, and electron magnetic chiral dichroism -- that allow studying individual nanoparticles down to sub-nanometer resolution with element, valence and magnetic selectivity, are presented. All in all, the intimate, fundamental correlation of the nanostructure (crystalline, chemical, magnetic) to the physical properties of the nanoparticles is ascertained.
format Preprint
id arxiv_https___arxiv_org_abs_2401_13422
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Magnetic nanoparticles: from the nanostructure to the physical properties
Batlle, Xavier
Moya, Carlos
Torroellla, Mariona Escoda
Iglesias, Oscar
Rodriguez, Arantxa Fraile
Labarta, Amilcar
Materials Science
Some of the synthesis methods and physical properties of iron-oxide based magnetic nanoparticles such as Fe3-xO4 and CoxFe3-xO4 are reviewed because of their interest in health, environmental applications, and ultra-high-density magnetic recording. Unlike high crystalline quality nanoparticles larger than a few nanometers that show bulk-like magnetic and electronic properties, nanostructures with increasing structural defects yield a progressive worsening of their general performance due to frozen magnetic disorder and local breaking of their crystalline symmetry. Thus, it is shown that single-crystal, monophasic nanoparticles do not exhibit significant surface or finite-size effects, such as spin canting, reduced saturation magnetization, high closure magnetic fields, hysteresis-loop shift or dead magnetic layer features which are mostly associated with crystallographic defective systems. Besides, the key role of the nanoparticle coating, surface anisotropy, and inter-particle interactions are discussed. Finally, the results of some single particle techniques -- magnetic force microscopy, X-ray photoemission electron microscopy, and electron magnetic chiral dichroism -- that allow studying individual nanoparticles down to sub-nanometer resolution with element, valence and magnetic selectivity, are presented. All in all, the intimate, fundamental correlation of the nanostructure (crystalline, chemical, magnetic) to the physical properties of the nanoparticles is ascertained.
title Magnetic nanoparticles: from the nanostructure to the physical properties
topic Materials Science
url https://arxiv.org/abs/2401.13422