2002 年 23 巻 11 号 p. 681-687
Perovskite-type doped manganites are ferromagnetic metals due to the so-called double-exchange mechanism. Recent experimental investigations, however, revealed that the double-exchange interaction strongly competes with the charge-ordering interaction. The competition causes the short-range charge-order in the paramagnetic phase and the phase separation observed in the vicinity of the phase boundary between the ferromagnetic metals and charge-ordered insulators. The competition is expected to govern also the pulse laser irradiation effects. In this article, we will introduce (1) temperature variation of the pulse laser irradiation effects on La0.7Ca0.3MnO3 film, (2) critical slowing down of the relaxation time of La0.7Ca0.3MnO3 film and (3) chemical substitution effects on the critical slowing down in La0.7Ca0.3MnO3 film. These experimental data are well understood in terms of the photoinduced formation of the short-range charge-order.