For certain combinations of temperature and magnetic field, the evolution with time of the magnetization of some phase-separated manganese oxides exhibits a unique steplike feature. This jump in the magnetization is proposed to correspond to a burstlike growth of the ferromagnetic fraction at the expense of the antiferromagnetic component, driven by the evolution of the strains at the interfaces between the two kinds of domains. These results bear a striking similarity with the phenomenon of an “incubation time” encountered in standard martensitic transformations.

• Received 30 July 2003

DOI:https://doi.org/10.1103/PhysRevB.68.220402