Novel collective magnetic relaxation phenomena in manganites: a spin-glass behavior?

摘要

Here we address many of the fundamental open questions regarding the glassy behavior of the magnetic/electronic phase segregated state in rare earth perovskites. Magnetic relaxation (AC/DC) support a scenario in which collective effects (memory, ageing, etc.) can be understood as due to intercluster interactions. We propose that the phase segregated state (PSS) constitutes a sort of self-generated assembly of magnetic clusters in which the magnetic interaction introduces collectivity among them. The strength of the interactions can be tuned by composition and/or magnetic field, through the control of the size and concentration of the magnetic clusters. These results are general, applicable to other systems close to a localized to itinerant transition, like cobaltates, cuprates, etc. (C) 2004 Elsevier B.V. All rights reserved.