Photo-induced effect of the electron-spin resonance on the charge-ordered state in Pr0.65Ca0.35MnO3

Electron-spin resonance (ESR) for the charge-ordered state in well-characte rized Pr0.65Ca0.35MnO3 exhibited significant change of both the absorption profile and the effective spin susceptibility upon injection of laser light with photon energy of 1.17 eV provided by Nd-YAG laser. The increase of th e effective spin susceptibility was clearly found out thanks to the injecti on of photons ire the temperature range 90 K-80 K, which is below the trans ition temperature from the antiferromagnetic charge ordered state to the ca nted antiferromagnetic spin alternation state, T(CAF)similar to 125 K. The temperature dependence of the change of the ESR profile excludes the possib ility of heating by laser light. The present result suggests that a kind of photo-induced insulator-metal transition may occur due to propagation of t he delocalized carriers via probable double exchange interaction in the cha rge-ordering collapsed state created by the injection of photons.