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Magnetic homogeneity in Fe-Mn co-doped NiO nanoparticles
Hur Abbas1, K Nadeem1, H Krenn2
1Department of Physics, International Islamic University, Islamabad 44000, Pakistan.
Nanotechnology
|September 5, 2020
Summary
Co-doping nickel oxide (NiO) nanoparticles with iron (Fe) and manganese (Mn) enhances magnetic homogeneity. This study reveals optimal doping concentrations for improved magnetic properties, making NiO nanoparticles promising for advanced magnetic applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Nickel oxide (NiO) nanoparticles possess potential for various magnetic applications.
- Understanding the influence of co-doping on NiO's magnetic properties is crucial for optimizing its performance.
Purpose of the Study:
- To investigate the effect of iron (Fe) and manganese (Mn) co-doping on the magnetic properties of antiferromagnetic (AFM) NiO nanoparticles.
- To determine the optimal doping concentrations for enhanced magnetic homogeneity and potential applications.
Main Methods:
- Rietveld refinement of powder X-ray diffractometry (XRD) patterns to confirm crystal structure and crystallite size (32-38 nm).
- Ferromagnetic resonance (FMR) and M-H loop measurements to assess magnetic inhomogeneity and room temperature ferromagnetism.
- Zero-field-cooled (ZFC) and field-cooled (FC) dc magnetization, and AC susceptibility measurements to analyze magnetic phase transitions.
- Neutron diffraction to confirm the antiferromagnetic order and probe magnetic coupling.
Main Results:
- Co-doping with Fe and Mn resulted in face-centred cubic NiO nanoparticles with an average crystallite size of 32-38 nm.
- 4%Mn-4%Fe co-doped NiO nanoparticles exhibited reduced local magnetic inhomogeneity.
- Room temperature ferromagnetism-like behavior was observed at higher Fe and lower Mn concentrations, attributed to double exchange interaction.
- ZFC/FC magnetization revealed surface freezing and blocking peaks, with higher blocking temperatures for 4%Mn-4%Fe and 2%Mn-6%Fe samples.
- An anomalous peak (Tx) in AC susceptibility was most prominent in 4%Mn-4%Fe co-doped nanoparticles, linked to ferromagnetic coupling between Fe and Mn ions.
- Neutron diffraction confirmed AFM order and super-exchange interaction between Ni, Fe, and Mn ions.
Conclusions:
- Small and equal doping concentrations of Fe and Mn in NiO nanoparticles significantly increase magnetic homogeneity.
- The observed ferromagnetic coupling between Fe and Mn ions at equal concentrations is key to enhanced magnetic properties.
- Optimized Fe and Mn co-doped NiO nanoparticles are attractive candidates for diverse magnetic applications.
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