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Dielectric Relaxation of NiFe2O4/Gd2O3 Core-Shell Nanoparticles
Journal of Nanoscience and Nanotechnology
|September 16, 2015
Summary
Synthesized gadolinium oxide (Gd2O3) encapsulated nickel-iron oxide (NiFe2O4) core-shell nanoparticles exhibit a band gap of 4.38 eV. Their dielectric relaxation properties were analyzed across a temperature range, obeying Arrhenius law.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Physics
Background:
- Core-shell nanoparticles offer unique properties due to their distinct material interfaces.
- Nickel-iron oxide (NiFe2O4) and gadolinium oxide (Gd2O3) are functional materials with potential applications in various fields.
- Understanding the dielectric and electrical properties of composite nanomaterials is crucial for device development.
Purpose of the Study:
- To synthesize and characterize Gd2O3 encapsulated NiFe2O4 core-shell nanoparticles (CSNPs).
- To investigate the optical properties, specifically the band gap, of the synthesized CSNPs.
- To analyze the frequency-dependent dielectric relaxation and electrical conductivity behavior over a range of temperatures.
Main Methods:
- Chemical synthesis route for creating NiFe2O4/Gd2O3 CSNPs.
- X-ray diffraction (XRD) for phase formation analysis.
- Transmission electron microscopy (TEM) for particle size determination.
- UV-visible absorption spectroscopy for band gap measurement.
- Impedance spectroscopy and dielectric measurements across a temperature range (303 K to 543 K).
Main Results:
- Successful synthesis of Gd2O3 encapsulated NiFe2O4 CSNPs with an average particle size of 60 nm.
- Determined a band gap of 4.38 eV for the CSNPs, falling between the individual band gaps of Gd2O3 and NiFe2O4.
- Dielectric relaxation times followed Arrhenius law with an activation energy of 0.3 eV.
- Impedance data analyzed using an RC equivalent circuit, and dielectric relaxation modeled by the Havriliak-Negami technique.
- Frequency-dependent conductivity spectra exhibited a double power law behavior.
Conclusions:
- The synthesized NiFe2O4/Gd2O3 CSNPs possess tunable optical properties and interesting dielectric relaxation characteristics.
- The temperature-dependent electrical behavior can be described by established physical models, indicating potential for temperature-sensitive applications.
- These core-shell nanostructures show promise for applications requiring specific optical and electrical responses.
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