Development and Application cf Bistability in Molecule-based Magnetic Mterials

自旋电子器件的科学和技术引起了人们极大的兴趣。在本项目中，我们开发了用于未来自旋电子学的分子基磁性材料。1）噻唑基自由基具有化学稳定性和强的分子间相互作用。我们对这一自由基家族进行了系统的研究，即化学合成、结构分析和物理测量，发现了室温磁双稳、光致相变、有机铁磁性等。2）分子/纳米磁体的发展是自旋电子学的关键问题。某些过渡金属簇合物的磁化曲线具有磁滞回线，因此被称为单分子磁体（SMM）。在这个项目中，我们对SMM进行了化学修饰，以阐明磁结构相关性并控制经典和量子磁弛豫。揭示了SMM中的磁结构相关性，并发展了新型纳米磁体的合成。我们成功地将氢氧化钴均匀地包覆在聚苯乙烯微球（O.D.300-1000 nm）上，得到了球形空心纳米铁钴磁体和尖晶石型Co_3O_4磁体。

The science and technology of spin electronic devices have attracted much interest. In this project, we developed molecule-based magnetic materials for future spintronics.1)Thiazyl radicals possess chemical stability and strong intermolecular interactions. We carried out a systematic study, namely, chemical syntheses, structural analyses, and physical measurements on this radical family, and discovered room-temperature magnetic bistability, photo-induced phase transition, organic ferromagnetism, etc.2)Development of molecular-/nano-magnets is a key issue for spintronics. Some of transition-metal cluster complexes exhibit a hysteresis loop on magnetization curve, so that they are called single molecule magnets(SMM). In this project, we performed chemical modifications on SMM, in order to elucidate the magneto-structural correlation and to control the classical and quantum magnetic relaxations. The magneto-structural correlation in SMM was revealed.We also developed synthesis of novel nanomagnets. We succeeded in uniform coating of polystyrene beads (O.D.300-1000 nm) with cobalt hydroxides, and obtained spherical hollow nanomagnets of fee Co and spinel Co_3O_4.