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Updated: May 5, 2026

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Interfacial magnetism and exchange coupling in BiFeO3-CuO nanocomposite
Kaushik Chakrabarti1, Babusona Sarkar, Vishal Dev Ashok
1Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032, India.
Bismuth ferrite (BiFeO3) nanocrystals and copper oxide (CuO) nanosheets form a composite exhibiting strong magnetic exchange coupling. This coupling induces an interfacial superparamagnetic phase and a significant exchange bias effect, enhancing coercivity in the nanocomposite.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Bulk Bismuth ferrite (BiFeO3) exhibits a spiral modulated spin structure.
- Antiferromagnetic Copper Oxide (CuO) serves as a matrix for BiFeO3 nanocrystals.
- Nanocrystal size reduction influences magnetic ordering in BiFeO3.
Purpose of the Study:
- To investigate the magnetic properties of BiFeO3/CuO nanocomposites.
- To explore the influence of magnetic exchange coupling on interfacial phases.
- To characterize the exchange bias effect in these novel materials.
Main Methods:
- Synthesis of (x)BiFeO3/(100-x)CuO nanocomposites with varying compositions.
- Characterization using X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM).
- Magnetic property measurements including temperature-dependent magnetization and hysteresis loops.
Main Results:
- Dispersion of 9 nm BiFeO3 nanocrystals within CuO nanosheets confirmed.
- Ferromagnetic ordering in BiFeO3 attributed to reduced particle size and surface spin disorder.
- Interfacial superparamagnetic phase observed due to strong magnetic exchange coupling, with a blocking temperature of ~80 K.
- Significant exchange bias effect below 170 K, with maximum HEB of 1841 Oe at 5 K for x=50.
- Exchange bias coupling enhances coercivity by 1934 Oe at 5 K.
Conclusions:
- Strong magnetic exchange coupling between BiFeO3 nanocrystals and CuO nanosheets is crucial for observed phenomena.
- The nanocomposites exhibit tunable magnetic properties and a notable exchange bias effect.
- Surface spin disorder and interfacial coupling play key roles in the magnetic behavior of BiFeO3/CuO nanocomposites.
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