Bending Deformation of Soft Magnetic Elastomer Under an External Magnetic Field

The paper deals with an experimental and theoretical study of bending deformation of a rod‐shaped magnetic elastomer, consisting of a soft polymer with embedded micron‐sized magnetic particles, under the action of a transverse magnetic field. Initially, the sample is situated on a horizontal substrate between poles of an electromagnet, creating a vertical magnetic field. One end of the magnetic rod is fixed; the other one is free. The sample's upward bending takes place when the field exceeds some threshold value B 1 . While the field decreases, the deformation disappears when the field becomes less than the second threshold value B 2 , which is significantly less than B 1 . So, the plot of the bending versus magnetic field presents a wide hysteresis loop. Two types of deformations are detected experimentally and explained theoretically: the monotonic increase of the deformation from the fixed end of the sample to the free one, and the non‐monotonic bend, with a maximum. Analysis shows that the spontaneous deformation can take place only if the field increases upward and the ponderomotive force acting on a filament segment dominates over gravity.