Frequency-temperature dependent dynamics of dielectrics in ferric oxoborate Fe3BO6 of cocktail structure of nanorods |
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Authors: | K. Kumari R.K. Kotnala |
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Affiliation: | 1. Materials Science Centre, Indian Institute of Technology , Kharagpur-721 302 , India;2. Magnetic Materials Division , National Physical Laboratory , New Delhi-110 012 , India |
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Abstract: | Oxoborates have both dielectric and magnetic properties useful for magnetodielectric devices, sensors, or biological tools. Such compounds Fe2BO4, Fe3BO5, or Fe3BO6 are known to grow easily as single crystals in a liquid flux. A polycrystalline phase forms only on controlled conditions of a solid state reaction of the basic oxides. In this study, we report highly dielectric Fe3BO6 when grown in a specific shape of nanorods (~200?nm diameter and 50–100?µm length) from an iron borate glass, which offers devisable shapes of sheets, discs, and fibers. Frequency (f)-temperature reliant dynamics of dielectric constant εr is studied over 25–300°C at 0.1–103?kHz frequencies. At low frequency such as 100?Hz, a large εr -value 40,000, better than most of high εr -value ferroelectrics, incurs at room temperature. At f?≥?50?kHz, although only an order of diminished εr -value lasts, it increases steadily with temperature, possibly due to increasing electrical conductivity in a specific resistor–capacitor network. Suppressed dielectric relaxation and spin-flops share a merely weak spin-reorientation transition near 160°C. A stable power loss ≤0.5 lasts at f?>?10?kHz useful for possible applications of magnetodielectric materials. |
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Keywords: | magnetodielectric materials oxoborates microstructure nanoceramics dielectric materials |
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