Magnetoelectric effect in nanogranular FeCo-MgF films at GHz frequencies.
Magnetoelectric effect in nanogranular FeCo-MgF films at GHz frequencies.
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DOI：
10.1016/j.jmmm.2017.08.088
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发表时间：
2018-01-15
影响因子：
2.7
通讯作者：
Yabukami S
中科院分区：
文献类型：
--
作者：
Ikeda K;Kobayashi N;Arai KI;Yabukami S
研究了纳米颗粒FeCo-MgF薄膜中的磁电效应。磁电效应和介电弛豫在频率超过10 MHz时得到证实。颗粒间距和弛豫时间随磁性金属浓度的增加而减小。磁电效应在松弛频率处达到最大值。磁电效应是材料科学的一个关键问题，在高频段尤为重要，在工业应用中不可或缺。在这里，我们首次研究了纳米颗粒feo -MgF薄膜中的高频隧穿磁介电（TMD）效应，该薄膜由分散在MgF绝缘体基质中的纳米大小的磁性FeCo颗粒组成。在超过10 MHz的频率下，介质弛豫和TMD效应得到了证实。介电弛豫的频率依赖性由Debye-Fröhlich模型描述，考虑了弛豫时间色散，这反映了微观结构性质的变化，如颗粒大小和颗粒之间的间距影响介电响应。TMD效应在与弛豫时间相反的频率处达到最大值。观察到峰值TMD效应的频率在12 MHz和220 MHz之间变化，这取决于纳米颗粒膜中磁性金属的浓度。薄膜的间距随磁性金属浓度的增加而减小，与弛豫时间一致。这些结果表明，介质弛豫是通过改变纳米结构和沉积条件来控制的。这些纳米颗粒薄膜的一个潜在应用是用于下一代移动通信系统的可调阻抗器件，频率超过1ghz，其中电容通过外加磁场控制。
Magnetoelectric effect in the nanogranular FeCo-MgF films has been investigated. Magnetoelectric effect and dielectric relaxation are confirmed at frequencies over 10 MHz. The inter-spacing of granules and the relaxation time decrease with increasing magnetic metal concentration. The magnetoelectric effect reaches a maximum at a relaxation frequency. The magnetoelectric effect is a key issue for material science and is particularly significant in the high frequency band, where it is indispensable in industrial applications. Here, we present for the first time, a study of the high frequency tunneling magneto-dielectric (TMD) effect in nanogranular FeCo-MgF films, consisting of nanometer-sized magnetic FeCo granules dispersed in an MgF insulator matrix. Dielectric relaxation and the TMD effect are confirmed at frequencies over 10 MHz. The frequency dependence of dielectric relaxation is described by the Debye-Fröhlich model, taking relaxation time dispersion into account, which reflects variations in the nature of the microstructure, such as granule size, and the inter-spacing between the granules that affect the dielectric response. The TMD effect reaches a maximum at a frequency that is equivalent to the inverse of the relaxation time. The frequency where the peak TMD effect is observed varies between 12 MHz and 220 MHz, depending on the concentration of magnetic metal in the nanogranular films. The inter-spacing of the films decreases with increasing magnetic metal concentration, in accordance with the relaxation time. These results indicate that dielectric relaxation is controlled by changing the nanostructure, using the deposition conditions. A prospective application of these nanogranular films is in tunable impedance devices for next-generation mobile communication systems, at frequencies over 1 GHz, where capacitance is controlled using the applied magnetic field.
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影响因子：
4.6
作者：
Kaiju H;Nagahama T;Sasaki S;Shimada T;Kitakami O;Misawa T;Fujioka M;Nishii J;Xiao G
通讯作者：
Xiao G
影响因子：
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通讯作者：
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通讯作者：
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作者：
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通讯作者：
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影响因子：
1.5
作者：
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通讯作者：
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