  We study the magneto-elastic coupling behavior of paramagnetic chains in soft
polymer gels exposed to external magnetic fields. To this end, a laser scanning
confocal microscope is used to observe the morphology of the paramagnetic
chains together with the deformation field of the surrounding gel network. The
paramagnetic chains in soft polymer gels show rich morphological shape changes
under oblique magnetic fields, in particular a pronounced buckling deformation.
The details of the resulting morphological shapes depend on the length of the
chain, the strength of the external magnetic field, and the modulus of the gel.
Based on the observation that the magnetic chains are strongly coupled to the
surrounding polymer network, a simplified model is developed to describe their
buckling behavior. A coarse-grained molecular dynamics simulation model
featuring an increased matrix stiffness on the surfaces of the particles leads
to morphologies in agreement with the experimentally observed buckling effects.
