Related Experiment Video
Updated: Sep 23, 2025
08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.6K
Nanosized tetragonal β-FeSe phase obtained by mechanical alloying: structural, microstructural, magnetic and
1Departamento de Física, Universidade Federal de Santa Catarina Campus Trindade 88 040-900 Florianópolis Santa Catarina - SC Brazil carlos.campos@ufsc.br.
RSC Advances
|May 11, 2022
Summary
Mechanochemical synthesis produced nanocrystalline tetragonal β-FeSe. Impurities and nanoparticle strain affect its poor superconductivity and semiconducting properties, with phase content increasing upon air exposure.
Area of Science:
- Materials Science
- Solid State Physics
- Nanotechnology
Background:
- Iron selenide (FeSe) is a material of interest for its superconducting properties.
- Mechanochemical synthesis offers a route to novel material phases and microstructures.
- Understanding phase formation and properties of β-FeSe is crucial for its applications.
Purpose of the Study:
- To prepare nanocrystalline tetragonal β-FeSe using a mechanochemical approach.
- To characterize the phase formation, crystal structure, and microstructure of the synthesized β-FeSe.
- To investigate the magnetic, electrical, and ageing properties of the mechanochemically synthesized material.
Main Methods:
- Ball milling of FeSe powder mixtures under an inert atmosphere.
- Annealing treatments at 400 °C under vacuum.
- X-ray powder diffraction (XRD) for phase analysis and Rietveld refinement.
- Microstructural analysis including crystallite size and microstrain determination.
- Magnetic and electrical property measurements.
- Observation of ageing effects in air.
Main Results:
- Pure β-FeSe phase was obtained after annealing for specific Fe:Se ratios (x=1.25, 1.50).
- Mechanochemical synthesis resulted in highly strained nanoparticles (<22 nm) with lattice contraction.
- Poor superconductivity at 4 K and semiconducting behavior were observed, attributed to impurity phases and nanostructural effects.
- An increase in β-FeSe phase content was observed with ageing in air.
Conclusions:
- Mechanochemical synthesis is a viable method for producing nanocrystalline β-FeSe.
- Nanoparticle strain and ferromagnetic impurities significantly influence the material's properties.
- Ageing in air promotes the formation of the β-FeSe phase, requiring further investigation.
