Magnetic materials have a long history. Magnets were discovered in ancient China and applied to the compass. Theoretical research on magnetism began hundreds of years ago in Europe, such as Faraday

Scientists. Traditional magnetic materials are alloys such as Nd2Fe14B and metal oxides such as Fe12O19. According to the characteristics of their composition based on ions or atoms, they can be called atom based magnets, which are characterized by the synthesis of inorganic magnets with Metallic bonding or ion bonds at high temperatures. With the development of high-tech, A so-called molecular based magnetic material has emerged with molecules containing organic components such as Cp * as building blocks, such as [FeCp * 2] (Cp * represents pentamethylpentylC5H5 (CH3) 5). Its characteristic is that it is synthesized under low energy consumption and low temperature conditions, easy to adjust its structure and function through molecular tailoring, and easy to be compatible with biological systems. Although the magnetic energy density is low, the mass density is also small. Molecular magnets, due to their unique properties, It quickly became a research hotspot.