Magnetism and Transport Properties for Organic-Inorganic Perovskite Films

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Metal halide-based layered perovskites, (RNH_3)_2MX_4, self-organized organic/inorganic multilayer structure were synthesized, where R is a simple alkylammonium molecule with a long chain length, (CH_3(CH_2)_<17>), methyl-benzene C_6H_5-CH_2, 1-methyl-naphthalene 1-C_<10>H_9-CH_2, 1-propylnaphthalene 1-C_<10>H_9-O(CH_2)_3 and 1-butyl-naphthalene 1-C_<10>H_9-O(CH_2)_4, M is 3d transition metal elements (Cr, Mn, Fe, Co, Ni, Cu, Zn), X is Cl and Br. Its layered perovskite structure was checked by a FT-IR method. The perovskites of CH_3(CH_2)_<17>NH_3 with Cu and Cr showed ferromagnetism (T_c7=10 K and 42 K, respectively), and Mu and Fe antiferromagnetism (T_N=41 K and 95 K, respectively). These results roughly corresponded to the results for methyl and ethyl ammonium complexes reported. The naphthlene complex with Cu also showed ferromagnetism, however, the Curie temperature became low. It was considered that the relative large chromophore might disturb the Jahn-Teller distortion of CuCl_6, octahedra. 1-methyl-naphthylamine- hydrochloride was luminous with the wavelength of 350 nm under ultraviolet light irradiation, but its Cu complex was quenched. Origin of different Curie temperatures, T_c, depending on the structure of the molecule were explained by taking into account of the overlap of the electronic states between the organic and the inorganic layers.