Inside Ceramics and Between MgO Grains: Solid-State Synthesis of Intergranular Semiconducting or Magnetic Spinels.

Autor: Schwab T; Department of Chemistry and Physics of Materials, Paris-Lodron University Salzburg, Jakob-Haringer-Straße 2a, Salzburg, A-5020, Austria., Aicher K; Department of Chemistry and Physics of Materials, Paris-Lodron University Salzburg, Jakob-Haringer-Straße 2a, Salzburg, A-5020, Austria., Zickler GA; Department of Chemistry and Physics of Materials, Paris-Lodron University Salzburg, Jakob-Haringer-Straße 2a, Salzburg, A-5020, Austria., Reissner M; Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, Vienna, A-1040, Austria., Diwald O; Department of Chemistry and Physics of Materials, Paris-Lodron University Salzburg, Jakob-Haringer-Straße 2a, Salzburg, A-5020, Austria.
Jazyk: angličtina
Zdroj: Small methods [Small Methods] 2024 Oct 29, pp. e2400715. Date of Electronic Publication: 2024 Oct 29.
DOI: 10.1002/smtd.202400715
Abstrakt: Configurations of composite metal oxide nanoparticles are typically far off their thermodynamic equilibrium state. As such they represent a versatile but so far overlooked source material for the intergranular solid-state chemistry inside ceramics. Here, it is demonstrated how the admixture of Fe 3+ and In 3+ ions to MgO nanoparticles, as achieved by flame spray pyrolysis, can be used to engage ion exsolution, phase separation, and subsequent spinel formation inside the network of diamagnetic and insulating MgO grains. Extremely high uniformity in the distribution of intergranular ferrimagnetic MgFe 2 O 4 films and grains with resulting magnetic coercivity values that depend on the nanoparticles' initial Fe 3+ concentration is achieved. Moreover, percolating networks of semiconducting MgIn 2 O 4 are derived from MgO nanoparticles with admixtures of 20 at% In 3+ that gives rise to an enhancement of dc conductivity values by more than five orders of magnitude in comparison to the insulating MgO host. The here presented approach is general and applicable to the synthesis of a variety of functional spinel nanostructures embedded inside ceramic matrices. Nanoparticle loading with aliovalent impurity ions, the level of nanoparticle powder density after compaction, and sintering temperature are key parameters for this novel type of solid-state chemistry in between the host grains.
(© 2024 The Author(s). Small Methods published by Wiley‐VCH GmbH.)
Databáze: MEDLINE
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