Journal of Applied Polymer Science, Vol.58, No.6, 1007-1013, 1995
Polyacrylamide Gels Filled with Ferromagnetic Anisotropic Powder - A Model of a Magnetomechanical Device
The concept of a magnetomechanical system able to show permanent magnetization if compressed or to deform in a uniform magnetic field, is presented. The system design is based on polyacrylamide gel filled with demagnetized hard ferrite particles. The ferrite filled gel is deformed by plane strain compression and magnetized while compressed. The orientation of individual magnetized particles was randomized upon compression release. Such samples exhibit no magnetic moment if decompressed and produce magnetic field intensity from 3 to 30 G if compressed. The samples exposed to external uniform magnetic field show macroscopic contraction or expansion of up to 40% of the initial dimensions. The most efficient ferrite was neodymium ferrite in the form of flakes.