Changes of thickness and self-excited oscillations of the conducting porous magnetoelast nearby percolation threshold caused by current flow

In this article a method of production was described of a permanently magnetized porous composite with elastic conducting matrix made of silicone. The contents of silver particles causing the matrix to possess conducting properties were slightly higher than a percolation threshold. The sample of this composite called magnetoelast was switched on in an electric circuit. Changes in a thickness of the sample were detected by Michelson interferometer. The self-excited oscillations of thickness and current intensity current of 147–244 Hz frequency were observed after the application of constant voltage to the sample. The changes of thickness and the oscillations were caused by an interaction of the current flowing through the sample with its internal magnetic field. The electrodynamics force produced as the result of this interaction caused the increase of the sample thickness and the decrease of the sample conductivity after exceeding the percolation threshold.