The origin of the so called magnetostriction effect, i.e., the deformation of a soft magnetic elastomer (SME) in response to a uniform magnetic field is discussed. We note that up to now there exists a number of cases, where the theory is unable to explain the facts well established for real SMEs. In our view, the essential issue, formerly not adequately accounted for, is the type of structural short-range order in the magnetic microparticle assembly. Two-dimensional model problems are formulated and solved, which demonstrate the validity of the hypothesis.

Ferrihydrite nanoparticles (2–5 nm in size) produced by bacteria Klebsiella oxytocain the course of biomineralization of iron salt solutions from a natural medium exhibit unique magnetic properties:...