Electronic structure, and magnetic and microwave absorption properties of Co-doped SrFe12O19 hexaferrites
| Autor: | Bo Wha Lee, The-Long Phan, Dong-Seok Yang, H.H. Nguyen, N. Tran, N. T. Dang |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Process Chemistry and Technology Doping Analytical chemistry 02 engineering and technology Electronic structure Coercivity 021001 nanoscience & nanotechnology 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Magnetization Lattice constant Oxidation state 0103 physical sciences Materials Chemistry Ceramics and Composites 0210 nano-technology Absorption (electromagnetic radiation) Microwave |
| Zdroj: | Ceramics International. 46:19506-19513 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2020.04.304 |
| Popis: | The crystalline and electronic structures and the magnetic and microwave absorption (MWA) properties of SrFe12-xCoxO19 (x = 0–1) hexaferrites have been studied. The structural analyses indicate that an increase in Co content (x) from 0 to 0.2 enhances slightly the lattice constant c while a reduces, proving Jahn-Teller distortions. A further increase in x causes a gradual decrease of both a and c. The electronic structure study indicates the co-presence of Fe2+ and Fe3+ in some doped compounds while Co is stable with the oxidation state 2+. Magnetization measurements for the doped compounds reveal a gradual enhancement of the saturation magnetization (Ms) from ~46.7 emu/g for x = 0.1 to 51.7 emu/g for x = 1. Meanwhile, the coercivity (Hc) tends to decrease from ~3.2 kOe for x = 0.1 to 1.7 kOe for x = 1. Such changes are correlated to a partial replacement of Co2+ for Fe2+,3+ in preferable sites. Investigating the MWA properties in the frequency range f = 1–12 GHz, we have found the compounds with x = 0.4 and 1 showing good MWA possibility. The best MWA performance corresponds to x = 0.4 with the thickness of 2 mm. Its minimum RL value obtained at f = 10.9 GHz is about −45.2 dB, meaning >99.99% microwaves being absorbed. The results reflect that the Co doping improved the magnetic and MWA properties of SrCoxFe12-xO19. |
| Databáze: | OpenAIRE |
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