Preparation and electrical characterization of MES-type magnetodielectric system based on Co-Al-O nanogranular films

摘要

The magnetodielectric (MD) material is a multifunctional material composited by many different functions from individual phenomena or effects. It can pos-sess both the dielectric conductivity obeyed the Mott-Efros-Shklovskii (MES) laws, referred to as MES-MD for short, and other properties, such as MD, superparamagnetic phenomena, spin-dependent tunneling, spin accumulation or confinement. Coulomb blockade, spin blockade, and Kondo effect. The multifunctional feature is expected to give novel physical properties or effects in electron transport. This work reports, such an MES-MD system, based on Co-Al-O thin films with the Co components below the percolation threshold (＜ 30 at.% to ensure the MES-MD feature), has been fabricated. The initial manifestations for the MES-MD features of the Co-Al-O films were analyzed through the microstructure characteristics, magnetic properties, and especially the electrical transport behaviors. Typical features, in addition to the SPM attribute, include the Coulomb blockade and the local Kondo effects, which are mainly demon-strated through the current-voltage, I(Ⅴ), and conductance-voltage, G(Ⅴ), characteristics.