Naslov
Structural Behavior and Spin-State Features of BaAl2O4 Scaled through Tuned Co3+ Doping

Autori
Vrankić, Martina ; Šarić, Ankica ; Bosnar, Sanja ; Barišić, Dario ; Pajić, Damir ; Lützenkirchen- Hecht, Dirk ; Jelovica Badovinac, Ivana ; Petravić, Mladen ; Altomare, Angela ; Rizzi, Rosanna ; Klaser, Teodoro

Izvornik
Inorganic chemistry (0020-1669) 60 (2021), 12; 8475-8488

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Doping ; Lattices ; Extended X-ray absorption fine structure ; Powder Diffraction ; Rietveld method ; Magnetization

Sažetak
Pure and Co3+-doped BaAl2O4 [Ba(Al1–xCox)2O4, x = 0, 0.0077, 0.0379] powder samples were prepared by a facile hydrothermal route. Elemental analyses by static secondary ion mass spectrometry (SIMS), X-ray absorption spectroscopy (XAS) measurements at the Co K- edge, and X-ray diffraction studies were fully correlated, thus addressing a complete description of the structural complexity of Co3+- doped BaAl2O4 powder. Powder X-ray diffraction (PXRD) patterns indicated that prepared samples were nanocrystalline with a hexagonal P63 symmetry. The X-ray absorption near-edge structure (XANES) measurements revealed the presence of cobalt in a +3 oxidation state, while the rarely documented, tetrahedral symmetry around Co3+ was extracted from the extended X-ray absorption fine structure (EXAFS) oscillation patterns. Rietveld structure refinements showed that Co3+ preferentially substitutes Al3+ at tetrahedral Al3 sites of the BaAl2O4 host lattice, whereas the (Al3)O4 tetrahedra remain rather regular with Co3+–O distances ranging from 1.73(9) to 1.74(9) Å. The underlying magneto- structural features were unraveled through axial and rhombic zero-field splitting (ZFS) terms. The increased substitution of Al3+ by Co3+ at Al3 sites leads to an increase of the axial ZFS terms in Co3+-doped BaAl2O4 powder from 10.8 to 26.3 K, whereas the rhombic ZFS parameters across the series change in the range from 2.7 to 10.4 K, showing a considerable increase of anisotropy together with the values of the anisotropic g- tensor components flowing from 1.7 to 2.5. We defined the line between the Co3+ doping limit and influenced magneto- structural characteristics, thus enabling the design of strategy to control the ZFS terms’ contributions to magnetic anisotropy within Co3+-doped BaAl2O4 powder.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

POVEZANOST RADA