Structural Behavior and Spin-State Features of BaAl2O4 Scaled through Tuned Co3+ Doping
Martina Vrankić1, Ankica Šarić1, Sanja Bosnar2
1Division of Materials Physics and Center of Excellence for Advanced Materials and Sensing Devices, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
Inorganic Chemistry
|June 1, 2021
Summary
Cobalt(III)-doped Barium Aluminate (BaAl2O4) powders were synthesized and characterized. The study reveals cobalt
Area of Science:
- Materials Science
- Solid State Chemistry
- Magnetism
Background:
- Barium aluminate (BaAl2O4) is a host lattice with potential applications in various fields.
- Doping with transition metals can significantly alter the magnetic and structural properties of host materials.
- Understanding the precise location and oxidation state of dopant ions is crucial for material design.
Purpose of the Study:
- To synthesize pure and Cobalt(III) (Co3+)-doped BaAl2O4 powders using a hydrothermal method.
- To comprehensively characterize the structural and magnetic properties of the synthesized materials.
- To investigate the influence of Co3+ doping on the BaAl2O4 lattice and its magneto-structural characteristics.
Main Methods:
- Hydrothermal synthesis for powder preparation.
- Static secondary ion mass spectrometry (SIMS) for elemental analysis.
- X-ray absorption spectroscopy (XAS) at the Co K-edge (including XANES and EXAFS) for oxidation state and local symmetry determination.
- Powder X-ray diffraction (PXRD) for structural analysis and crystallite size.
- Rietveld structure refinement for detailed structural parameters.
- Analysis of zero-field splitting (ZFS) terms to understand magnetic anisotropy.
Main Results:
- Co3+ ions were successfully incorporated into the BaAl2O4 lattice, substituting Al3+ at tetrahedral Al3 sites.
- XAS confirmed the presence of Co3+ in a tetrahedral coordination within the BaAl2O4 host.
- Rietveld refinements indicated that the (Al3)O4 tetrahedra remained relatively regular upon doping.
- Increased Co3+ substitution led to a significant increase in both axial and rhombic ZFS terms, enhancing magnetic anisotropy.
- Anisotropic g-tensor components increased from 1.7 to 2.5 with increasing Co3+ doping.
Conclusions:
- The study successfully correlated structural and magnetic properties of Co3+-doped BaAl2O4.
- Co3+ doping at tetrahedral Al3 sites in BaAl2O4 influences magneto-structural characteristics.
- The findings provide a strategy for controlling magnetic anisotropy in Co3+-doped BaAl2O4 by managing ZFS terms.
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