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Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties
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Multifunctional nanostructured Co-doped ZnO: Co spatial distribution and correlated magnetic properties
Rafael T da Silva1, Alexandre Mesquita, Angela O de Zevallos
1Instituto de Ciências Exatas, Universidade Federal de Alfenas - UNIFAL-MG, 37133-840 Alfenas, MG, Brazil. bonette@gmail.com.
Physical Chemistry Chemical Physics : PCCP
|July 25, 2018
Summary
This study reveals cobalt (Co) doping in zinc oxide (ZnO) nanoparticles passivates surfaces, inhibiting growth and suppressing ferromagnetism. Observed magnetism stems from surface defects and adsorbed elements, not bulk doping.
Area of Science:
- Materials Science
- Nanotechnology
- Condensed Matter Physics
Background:
- Diluted magnetic semiconductors (DIMS) are promising for spintronic applications.
- Controlling magnetism in Co-doped ZnO nanoparticles remains challenging.
- Surface effects significantly influence nanoscale material properties.
Purpose of the Study:
- To systematically analyze the structural and magnetic properties of Co-doped ZnO nanoparticles.
- To elucidate the spatial distribution of Co ions and its impact on magnetism.
- To develop a model explaining nucleation, growth, and magnetic ordering mechanisms.
Main Methods:
- Microwave-assisted hydrothermal synthesis for Co-doped ZnO nanoparticle preparation.
- Comprehensive structural analysis (e.g., X-ray diffraction).
- Magnetic property characterization and theoretical modeling.
Main Results:
- Confirmed Co ion incorporation into the wurtzite ZnO lattice.
- Identified primary Co concentration at the nanoparticle surface, passivating the surface and inhibiting growth.
- Observed ferromagnetism attributed to surface defects and adsorbed elements, not bulk doping.
Conclusions:
- Surface passivation by Co ions plays a critical role in Co-doped ZnO nanoparticle formation.
- A kinetic-thermodynamic model explains nanoparticle nucleation and growth.
- Surface-related phenomena are key to understanding the magnetic behavior of Co-doped ZnO systems.
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