Photoinduced spin-state transition ofCo3+ in the layered perovskite manganite thin film

Abstract

The photoinduced effect, at different temperatures, on layered perovskite manganiteLa1.2Sr1.8Mn1.8Co0.2O7 thin filmdeposited on a SrTiO3(100) substrate has been studied using a He–Ne laser (632.8 nm) with the power ofoutput 25 mW at low temperatures. The electrical transport and magneticproperties of the film are investigated systematically in the temperature regionfrom 20 to 300 K. The resistance shows a significant decrease at low temperatures(T<90 K) under laser irradiation, which can be interpreted in terms of the spin-state transition ofCo3+ ions. The magnetic field combined with the laser is also used to detect the photoinducedeffect of the spin-glass state. The time dependence of the metastable system underseveral applied fields was also discussed. The system has the ability to keep apersistent memory of the magnetic history imprinted in its zero-field resistance.