  Amongst the various fascinating types of material behavior featured by
magnetic gels and elastomers are magnetostrictive effects. That is,
deformations in shape or changes in volume are induced from outside by external
magnetic fields. Application of the materials as soft actuators is therefore
conceivable. Mostly, straight contraction or extension of the materials along a
certain direction is discussed and investigated in this context. Here, we
demonstrate that various further, different, higher modes of deformation can be
excited. To this end, different spatial arrangements of the magnetizable
particles enclosed by the soft elastic matrix, which constitute the materials,
need to be controlled and realized. We address various different types of
spatial configurations of the particles and evaluate resulting types of
deformation using theoretical tools developed for this purpose. Examples are
sheet-like arrangements of particles, circular or star-shaped arrangements of
chain-like aggregates, or actual three-dimensional star-like particle
configurations. We hope to stimulate with our work the development of
experimental design and engineering methods so that selected spatial particle
arrangements in magnetic gels and elastomers can be put to reality. Overall, we
in this way wish to promote the transfer of these promising class of materials
to real-world applications.
