Local-Field-Induced Effective Magnetic Hysteresis of Molecular Magneto-Optical Effects in the Visible Region at Room Temperature: Phthalocyanine Thin Films on Ferromagnetic Inorganic Substrates
journal contributionposted on 29.10.2009, 00:00 by Kazuyuki Ishii, Kazutaka Ozawa
We report the first observation of molecular magneto-optical effects due to a π-conjugated system with local-field-induced magnetic hysteresis in the visible region at room temperature. Thin films were prepared on a ferromagnetic substrate (Ni and SrO·6Fe2O3) using ditrihexylsiloxy(tetra-tert-butylphthalocyanato)silicon (SiPc(OTHS)2) since its surrounding substituents would prevent both aggregation and direct interaction with the ferromagnetic substrates. The magneto-optical effects of the diamagnetic SiPc(OTHS)2 on the Ni and SrO·6Fe2O3 substrates show the magnetic field dependences that are similar to the corresponding substrates. In the case of the SrO·6Fe2O3 substrate, this is the first observation of magnetic hysteresis of the magneto-optical effects due to the π-conjugated system in the visible region at room temperature. The magnetic field dependences of the molecular magneto-optical effects can be explained by the interfacial magnetic field of the ferromagnetic inorganic substrates. Molecular magneto-optical effects coupled with ferromagnetic materials have several advantageous features such as a remanent magneto-optical effect at room temperature, facile preparation of thin films by the cast method, and a sharp signal with changeable wavelength and intensity.