Synthesis of the polycrystalline Ba2-xSrxNi2(Fe1-yAly)12O22 (x = 0.0, 1.5, y = 0.00, 0.01, and 0.03) was accomplished by employing the polymerizable complex method. The samples were investigated for the crystallographic and magnetic properties by x-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Mössbauer spectrometer. Based on the results of the refined XRD patterns, all samples were confirmed to have a rhombohedral structure with space group R-3m. Moreover, six distinguished sublattices were identified, which were four octahedral sites (18hVI, 3bVI, 6cVI, and 3aVI) and two tetrahedral sites (6cIV*, 6cIV). The lattice constant of a0 and c0 decrease via Sr, Al substitution because the ionic radius of Sr2+ (1.12 Å) is smaller than that of Ba2+ (1.34 Å), and the ionic radius of Al3+ (0.535 Å) is smaller than that of Fe3+ (0.645 Å). The zero-field-cooled (ZFC) measurement was applied at 100 Oe between 4.2 and 295 K and it revealed the spin transition temperature (TS). Substitution of Sr ions increased TS. Al ions were further substituted after the substitution of Sr ions, and TS increased above room temperature. The Mössbauer spectra fit six distinguish sublattices: 18hVI, 3bVI, 6cIV, 6cIV*, 6cVI, and 3aVI. The isomer shift of all samples indicated that the charge state of Fe ions is Fe3+. The Mössbauer spectra obtained with respect to temperature change confirmed the changes in the magnetic hyperfine field curves at Ts.
CITATION STYLE
Kim, J., Choi, H., & Kim, C. S. (2020). Magnetic properties of polycrystalline Y-type hexaferrite Ba2-xSrxNi2(Fe1-yAly)12O22 using Mössbauer spectroscopy. AIP Advances, 10(1). https://doi.org/10.1063/1.5130045
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