Lappas, A;
Antonaropoulos, G;
Brintakis, K;
Vasilakaki, M;
Trohidou, KN;
Iannotti, V;
Ausanio, G;
... Bozin, ES; + view all
(2019)
Vacancy-Driven Noncubic Local Structure and Magnetic Anisotropy Tailoring in FeₓO-Fe₃-{δ}_O₄ Nanocrystals.
Physical Review X
, 9
(4)
, Article 041044. 10.1103/PhysRevX.9.041044.
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Abstract
In contrast to bulk materials, nanoscale crystal growth is critically influenced by size- and shape-dependent properties. However, it is challenging to decipher how stoichiometry, in the realm of mixed-valence elements, can act to control physical properties, especially when complex bonding is implicated by short- and long-range ordering of structural defects. Here, solution-grown iron-oxide nanocrystals (NCs) of the pilot wüstite system are found to convert into iron-deficient rock-salt and ferro-spinel subdomains but attain a surprising tetragonally distorted local structure. Cationic vacancies within chemically uniform NCs are portrayed as the parameter to tweak the underlying properties. These lattice imperfections are shown to produce local exchange-anisotropy fields that reinforce the nanoparticles’ magnetization and overcome the influence of finite-size effects. The concept of atomic-scale defect control in subcritical-size NCs aspires to become a pathway to tailor-made properties with improved performance for hyperthermia heating over defect-free NCs.
| Type: | Article |
|---|---|
| Title: | Vacancy-Driven Noncubic Local Structure and Magnetic Anisotropy Tailoring in FeₓO-Fe₃-{δ}_O₄ Nanocrystals |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevX.9.041044 |
| Publisher version: | https://doi.org/10.1103/PhysRevX.9.04104 |
| Language: | English |
| Additional information: | © 2020 American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Nanocrystals, High-resolution electron microscopy, Monte Carlo methods, X-ray pair-distribution function analysis |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10088471 |
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