Mössbauer spectroscopic study of photo-sensitive organic–inorganic hybrid system, (SP)[Fe(II)Fe(III)(dto) 3](dto = C 2O 2S 2, SP = spiropyran)

Abstract

A photo-sensitive organic–inorganic hybrid system (SP)[Fe IIFe III(dto) 3] (SP = spiropyran, dto = C 2O 2S 2), has recently been developed, where the photo-isomerization of the intercalated spiropyran in solid state triggers the change of the magnetic properties, including the ferromagnetic transition temperature from 5 to 22 K. We performed 57Fe Mössbauer measurement in order to probe the microscopic states of iron ions in (SP)[Fe IIFe III(dto) 3] and have investigated the photo-induced effect on them. The sample without UV-irradiation shows the charge transfer phase transition between 200 and 70 K and the higher and lower temperature phases coexist below 70 K, whereas the UV-irradiated sample does not undergo the charge transfer phase transition and the higher temperature phase is stable between 200 and 6 K.