Structural, dielectric and magnetic properties of BaFe 12−x Al x O 19 hexaferrite thick films
| Autor: | Sukhleen Bindra Narang, Chhavi Pahwa, Santhoshkumar Mahadevan, Puneet Sharma |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Scanning electron microscope Analytical chemistry 02 engineering and technology Dielectric Coercivity 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Grain size Electronic Optical and Magnetic Materials Bond length Impurity 0103 physical sciences Curie temperature 0210 nano-technology High-κ dielectric |
| Zdroj: | Journal of Magnetism and Magnetic Materials. 441:465-474 |
| ISSN: | 0304-8853 |
| Popis: | BaFe 12−x Al x O 19 (0 ≤ x 0 ≤ 2.5) powders and thick films were prepared by solid state synthesis method and screen printing technique respectively. X-ray diffraction confirmed the single phase without any impurity phase. Bond length calculation from FTIR spectra suggested the occupation of Al 3+ ions at octahedral and tetrahedral sites. Magnetic measurements showed that coercivity ( H c ), saturation magnetization ( M s ) and anisotropic field ( H a ) strongly depends on the substitution amount. As compared to the powder, substituted thick films possess higher H c despite its larger grain size. M-T measurement showed a decrease in Curie temperature from ∼497 °C ( x = 0.0) to ∼437 °C ( x = 2.0). High dielectric constant ( e r ) and low losses (tan δ ) were observed in Al 3+ substituted samples. However, e r decrease and tan δ increase with temperature. Scanning electron micrographs showed that Al 3+ substitution promotes hexagonal shaped grains in sintered thick films. Complex permeability behavior in X-band frequency is also investigated and found to be less in Al-substituted samples. Reflection losses are increased with Al 3+ substitution and found maximum (−47 dB at 9.3 GHz) for x = 1.5. |
| Databáze: | OpenAIRE |
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