The origin of the glassy magnetic dynamics of the phase segregated state   in perovskites
  In this paper we address many of the fundamental open questions regarding the glassy behavior of the magnetic/electronic phase segregated state in rare earth perovskites. In particular, magnetic relaxation experiments support that the collective effects (memory, ageing, etc.) are due to interparticle interactions, rather than the double-exchange vs. superexchange competition. A careful study of the non-linear susceptibility in the critical region is performed, and the critical exponents contrasted with those of conventional spin-glasses and concentrated quenched ferrofluids. The phase segregated state constitutes a sort of self-generated assembly of magnetic particles in which magnetic interaction introduces collectivity among the clusters. 
F. Rivadulla, M. A. Lopez-Quintela, J. Rivas