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Updated: Jul 16, 2025
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
The size effect of BiFeO3 nanocrystals on the spatial spin modulated structure
N E Gervits1, A V Tkachev1, S V Zhurenko1
1Lebedev Physical Institute, Russian Academy of Sciences, 119991, Moscow, Russia. ngervits@gmail.com.
Nanocrystal size reduction preserves the spatial spin modulated structure (SSMS) in bismuth ferrite, enhancing magnetic properties. This finding offers potential for advanced multiferroic materials.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Bulk BiFeO3 exhibits a cycloid-type spatial spin modulated structure (SSMS) that hinders linear magnetoelectric effects.
- Nanoscale reduction of crystal size is explored as a method to modify this SSMS.
Purpose of the Study:
- To investigate the impact of nanocrystal size on the SSMS in BiFeO3.
- To understand how SSMS changes with decreasing crystal size and its effect on magnetic properties.
Main Methods:
- Zero-field NMR (ZF NMR) spectroscopy for direct observation of local magnetic fields and SSMS.
- X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and magnetometry for structural and magnetic characterization.
Main Results:
- SSMS persists and becomes more harmonic as nanocrystal size approaches the cycloid period.
- Anisotropy changes from "easy axis" to "easy plane" with decreasing size.
- Significant increases in saturation magnetization, remanent magnetization, coercivity, and exchange bias observed in nanocrystals near the cycloid period.
Conclusions:
- SSMS is retained in BiFeO3 nanocrystals down to the cycloid period, with altered harmonicity and anisotropy.
- Reduced crystal size leads to substantially enhanced magnetic properties, suggesting potential for applications.
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