Novel dynamical effects and persistent memory in phase separated manganites

P. LEVY; F. PARISI; L. GRANJA; E. INDELICATO; G. POLLA

PHYSICAL REVIEW LETTERS

Año: 2002 vol. 89 p. 137001 - 137005

0031-9007

The time dependent response of the magnetic and transport properties of Fe-doped phase separated (PS) manganite La0.5Ca0.5MnO3 is reported. The nontrivial coexistence of ferromagnetic (FM) and non-FM regions induces a slow dynamics which leads to time relaxation and cooling rate dependence within the PS regime. This dynamics influences physical properties drastically. On one hand, metalliclike behavior, assumed to be a fingerprint of percolation, can be also observed before the FM phase percolates as a result of dynamical contributions. On the other hand, two novel effects for the manganites are reported, namely, the rejuvenation of the resistivity after aging and a persistent memory of low magnetic fields (<1 T), imprinted in the amount of the FM phase.