The studies on single molecular magnets (SMM’s) are in the interface between molecule based magnets and nanoscale magnetic materials.

first observed macroscopic quantum tunneling (MQT) on Mn_(12)-Ac in 1996, the research on single molecular magnets (SMM) such as Mn_(12)-Ac has received much attention.

A brief introduction to the main facets of the field is presented,and several recent topics,including intramolecular magnetic coupling and molecular magnetic engineering,molecular-based ferromagnets,single-molecular magnets,spin-transition complexes and magnetic coupling in biological systems,are briefly reviewed.

The research progress of molecule-based magnets,single-molecule magnets,single-chain magnets and molecular spin-transition complexes in this field is summarized,and the prospects is also discussed in this paper.

It is found that the system in ferromagnetic (FM) phase is dominated by single magneton scattering showing metallic-type conduction which can be fitted by the formula ρ=ρ_0+AT~2, here ρ is res.

It is shown that the magnetic monopole and the electric monopole can be generated on an unified model based on the Hopf bundle ( S 3=S 2×S 1 ) with the structure group U (1) .

Using quantion theory,this paper researches existence of magnetic monopole,and further,obtains the important characteristics about quantization of electric charge.

This paper discusses the existence of the magnetic monopole, the conclusion of which is that the magnetic monopole does not exist in the material world but exists in the hypothetical vacuum world.