Preparation and properties of left-handed electro-conductive microcoils

An inductor has been utilized in many electrical and magnetic applications. Recently, down-sizing of the inductor has been required because of the miniaturization of various kinds of devices. Furthermore, the fabrication of free standing microcoil has become very important for the next modification with the appropriate functional materials. Carbon microcoils are, for instance, applied for electromagnetic wave absorber. We have proposed that helical tissues in the fibrovascular bundles can generate the free standing conductive microcoils using the electroless plating and the resulting microcoils can exhibit the electromagnetic properties based on the coil size and the kind of coating metals. SEM image of the vascular bundle after Ag coating revealed that the particles of around100 nm were fully deposited onto the surface. The electric resistivity of the Ag microcoil was found as 10^-6Ωcm, leading to successful plating on the helical tissue template. Magnetic characteristics of the Ag microcoils by SQUID were examined here. The induced magnetization of the Ag microcoil linearly increased with increasing passed current, meaning consistent behavior with the electromagnetic induction theory. Inductance (∼10^-10 H) was in good agreement with the calculation from the geometrical structure of the microcoils. It was concluded that Ag microcoils prepared from helical tissues by electroless plating had high conductivity and showed electromagnetic induction property.