Effects of Grain Size on Magnetic and Dielectric Properties of Ferrites at Millimeter-Wave Frequencies
Effects of Grain Size on Magnetic and Dielectric Properties of Ferrites at Millimeter-Wave Frequencies
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毫米波频率下晶粒尺寸对铁氧体磁性能和介电性能的影响
DOI：
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发表时间：
2015
影响因子：
2.1
通讯作者：
Anjali Sharma
中科院分区：
文献类型：
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作者：
M. Afsar;Anjali Sharma
研究了微米级和纳米级六方晶系铁氧体的本构材料特性。一个准光学导波光谱仪连同三个返波振荡器作为辐射源被用来表征样品在宽的频率范围从30到120 GHz。已发现的构成材料的性能是依赖于样品中的颗粒的内部形态。已经进行了X射线衍射研究以研究颗粒的结构。提出了一种估算不同颗粒结构样品铁磁共振频率的模型。只有当纳米颗粒的尺寸约为单畴的尺寸时，才能观察到纳米颗粒的铁磁共振。与微米级粉末相比，纳米级粉末的共振强度要弱得多。对于纳米尺寸的粉末，共振频率峰向低频移动。
Constitutive material properties of microsize and nanosize hexagonal ferrites have been studied. A quasi-optical guided-wave spectrometer together with three backward-wave oscillators as the sources of radiation were used to characterize the samples in the broad frequency range from 30 to 120 GHz. The constitutive material properties have been found to be dependent on the internal morphology of the particles in the samples. X-ray diffraction studies have been carried out to study the structure of the particles. A model to estimate the ferromagnetic resonance frequency of the samples with different particle structures has been proposed. The ferromagnetic resonance for nanosize powders can only be observed if the particle size is about the size of a single domain. The resonance intensity is much weaker for the nanosize powder compared with the microsize powder. For the nanosize powders, the resonance frequency peaks shift to lower frequencies.