Electromagnetomechanical coupling response of plastoferrites.

The impetus of this work was to investigate the electromagnetic and tensile properties of several commercially available plastoferrites (PFs) at ambient conditions. The approach involved selection of a set of PFs, and measuring their complex effective permittivity ε = -jε" under uniaxial stress at microwave frequencies in the range 0.1-4.5 GHz at room temperature. The E' spectra have been analyzed for intensively strained PFs up to 3%. Comparing the experimental e values against several dielectric relaxational behaviours, we find that the main physics cannot be understood with a single relaxation mechanism. More importantly we show that the ε measurements under stress can be explained in terms of a Gaussian molecular network model in the limit of low stress. The present results have important applications in magnetoactive smart composite materials, e.g. flexible circuit technology in the electronics industry (sensors, actuators and micromechanical systems), functionalized artificial skin and muscles for robotic applications. [ABSTRACT FROM AUTHOR]