Novel insights into the magnetic behavior of non-stoichiometric LaMnO3+δ nanoparticles
| Autor: | José M. González-Calbet, M. Luisa Ruiz-González, Kevin M. Sigcho-Villacís, Raquel Cortés-Gil, José Luis Martínez, Jose M. Alonso, Antonio Hernando, Alberto Azor-Lafarga |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Magnetoresistance Electron energy loss spectroscopy Nanoparticle 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Ion Ferromagnetism Chemical physics Vacancy defect Scanning transmission electron microscopy Materials Chemistry Antiferromagnetism 0210 nano-technology |
| Zdroj: | Journal of Materials Chemistry C. 9:10361-10371 |
| ISSN: | 2050-7534 2050-7526 |
| DOI: | 10.1039/d0tc05972b |
| Popis: | LaMnO3+δ is one of the classical-formal nonstoichiometric systems in materials science that, for δ = 0, shows antiferromagnetic ordering by super-exchange interactions between Mn3+ ions. Nevertheless, the chemical reactivity of solids goes through different pathways when the particle size is reduced to the nanometric range, leading to the modification of the physico-chemical properties of materials. It is demonstrated here that octagonal LaMnO3+δ nanoparticles of average size 20 nm significantly modify their non-stoichiometry, microstructure and magnetotransport properties and are thus able to tune their behavior, as a function of the cationic vacancy concentration. For δ = 0, LaMnO3 nanoparticles, even with only Mn3+, become ferromagnetic, whereas for δ = 0.23, i.e. La0.93Mn0.93O3, due to a cationic diffusion mechanism, weaker ferromagnetic interactions appear promoting the emergence of magnetoresistance. This accommodation of compositional variations triggers Mn3+ → Mn4+ oxidation and facilitates, as observed by atomically resolved scanning transmission electron microscopy and electron energy loss spectroscopy, the displacement of some La atoms around their normal site that can introduce restrictions in double exchange Mn3+–O2−–Mn4+ interactions. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|