金属磁性纳米颗粒复合材料的左手特性

Left-handed characteristic of metallic magnetic nanoscale granular composites

研究了具有单轴各向异性的单畴铁磁颗粒复合体系实现左手特性的可能性.应用LLG方程,计算了复合体系中磁性颗粒的平均磁导率,并通过有效媒质理论Bruggeman方程得到纳米磁性金属颗粒复合体系的有效介电常数eε和有效磁导率μe及其在有限频率下的响应特性,以及该磁性金属颗粒体系的波矢k和平均波印廷矢量Sω与频率之间的变化关系.当一束平面波(其波长远大于磁性颗粒尺寸)在该复合介质中传播时,我们发现在一定的频率范围内,波矢k和平均波印廷矢量Sω的矢量点积小于零,即Sω.Re(k)<0,即在该频率范围内此磁性金属颗粒复合材料具有左手特性.

We studied the composite system which consists of the single-domain ferromagnetic particles with uniaxial anisotropy, it may be obtained the left-handed characteristic in the composite system. We derived the average susceptibility of magnetic particles of the composite system by using of the LLG equation and also obtained the effective permittivity εe and the effective permeability μe via the Bruggeman formula in finite frequencies, along with the wave vector κ and the average poynting＇ s vector S. When a plane wave （the wavelength λ 〉〉R of the magnetic particle radius） propagates in the composite system, in some frequency range, we found that the scalar product of the wave vector κ and the average poynting＇s vector S at the finite frequencies is less than zero,namely Sω,. Re（k ）〈 0, therefore the composite may show the so called left-handed characteristic in this frequency range.