单分子磁体

单分子磁体是涉及合成化学、材料科学和凝聚态物理等边缘学科的一个新颖课题。本文对单分子磁体的主要性质、功能、研究方法和最新进展做了评述。重点介绍了含Mn和Fe这两类重要的单分子磁体。

Single-Molecular Magnets

Many polynuclear clusters with nano-scale have high spins (S) in the ground states, which have large mag-neto-anisotropy and zero-field splitting. They could be magnetized by external magnetic fields and hold this state while below a critical temperature. These compounds are called single-molecular magnets (SMM), whose be-haviours are similar to those of bulk magnets. The most important of these properties are slow relaxation and quantum tunneling. The research on nano cluster is important not only for fundamental point of view but also for their application. The synthesis of clusters comprising mixed-valent transition-metal ions and organic ligards, for example, [Mn₁₂O₁₂(O₂CMe)₁₆(H₂O)₄], has been attempted with the aim to get new SMM for about ten years. Some other types of SMM such as some cyanide-bridge clusters have also been found recently. SMM is a novel area which is involved in several frontier sciences including synthetic chemistry, advanced material and condensate-state physics, etc. The main properties, functions, physical methods, and prospect on SMM are briefly introduced with the emphasis on two typical clusters of Mn and Fe. For achieve the goal of ap-plication, we need to search new class of SMM in the future which have higher magnetization and can be use at room temperature.