Development of functional materials has been an attractive issue in the fields of chemistry, physics, and materials science. Up to date, we have reported various unique magnetic functional materials using cyano-bridged bimetallic assemblies. Furthermore, we have developed novel metal oxides, epsilon-iron oxide (ε-Fe2O3 and lambda-trititanium pentaoxide (λ-Ti3O5), which are firstly obtained by chemical nanoscale synthesis.
Octacyano-Bridged Bimetallic Assemblies: We have developed several octacyano-bridged bimetallic assemblies showing photomagnetization. Among them, Fe2[Nb(CN)8](4-pyridinealdoxime)8∙2H2O is the first example showing photoreversible light-induced spin-crossover phenomenon. Furthermore, we have synthesized a chiral photomagnet, Fe2[Nb(CN)8](4-bromopyridine)8∙2H2O. By alternatively irradiating with blue and red lights, spontaneous magnetization was reversibly switched. As an second harmonic generation (SHG) nonlinear optical effect, we observed 90º switching of the polarization plane of the output SH light by changing the state of the magnet with 473-nm and 785-nm lights.
Multifunctional Prussian blue analogs: We have reported various functionalities on Prussian blue analogs. Recently, we have reported cesium detection by THz light in Cs cyanide-bridged manganese-iron framework. The basic concept is as follows: If a heavy atom is encapsulated in a cage of a porous material, the atom should vibrate slowly and resonate with a low-frequency terahertz light. Based on this concept, we carried out first-principles phonon mode calculations and terahertz time-domain spectroscopy measurements of Cs cyanide-bridged manganese-iron framework. The vibration mode of the Cs ion was found to be at 1.5 THz, which is significantly apart from other lattice vibrations. We developed a non-contact THz-light detection method for Cs ions. Furthermore, using rubidium manganese hexacyanoferrate as demonstration system, we reported a logical strategy for designing a phase transition accompanying a thermal hysteresis loop by combining first-principles phonon mode calculations and statistical thermodynamic calculations considering cooperative interaction, and we show the well agreement between the theoretical prediction and experimental results.
Huge coercive field and high-frequency millimeter wave absorption of ε-Fe2O3: We obtained pure ε-Fe2O3 and found that it has a huge coercive field over 20 kOe at room temperature and shows high-frequency millimeter wave absorption at 182 GHz. These properties can be widely tuned by metal-substitution. This material is a strong candidate for next generation high-density magnetic recording media and millimeter wave absorbing material, and in fact, ε-Fe2O3 is displayed at Science Museum London (UK) in a special exhibition on big data and information security.
Light- and pressure- induced metal-semiconductor phase transition in λ-Ti3O5: A novel phase of Ti3O5 (λ-Ti3O5) was prepared as nanoparticles. Phase transition between λ-Ti3O5 (metallic conductor) and β-Ti3O5 (semiconductor) was repeatedly observed at room temperature by light irradiation. Furthermore, reversible switching is also induced by other external stimuli such as pressure. This material exhibits high performance heat storage properties, called Long-term heat storage ceramics, which are understood from thermodynamic studies.
主 持 人：徐淮良 教授
报告时间：2018年09月03日 10:00
报告地点：唐敖庆楼D311报告厅
主办单位：电子科学与工程学院
集成光电子学国家重点实验室
物质科学吉林省高校高端科技创新平台
