5,000 years ago, humans discovered natural magnets (Fe3O4)
2300 years ago, the Chinese used a natural magnet to be scooped on a smooth surface. Under the action of geomagnetism, the guide of the spoon handle, 曰 "Si Nan" is the world's first guide.
1000 years ago, the Chinese used magnets and iron needles to frictionally magnetize them to make the world's first compass.
Around 1100, China integrated the magnet needle and the square λ disk into a magnet-type guide for navigation.
1405-1432 Zheng He began his great pioneering work in the history of mankind with his guide.
1488-1521 Columbus, Gamma, Magellan made a world-famous maritime discovery with a guide from China.
1600 British William Gilbert published a monograph on the magnet "magnet", repeating and developing the understanding and experimentation of the predecessors about magnetism.
1785 French physicist C. Coulomb used the twist to establish the "Coulomb's law" describing the force between the charge and the pole.
1820 Danish physicist H.C. Oster found that current induced magnetic force. 1831 British physicist M. Faraday discovered the phenomenon of electromagnetic induction.
1873 British physicist J.C. Maxwell completed a unified electromagnetic theory in his monograph "On electricity and magnetism."
1898-1899 French physicist P. Curie discovered that ferromagnetic materials become paramagnetic at specific temperatures (Curie temperature).
1905 French physicist P.I. Lang Zhiwan explained the paramagnetic variation with temperature based on statistical mechanics theory.
1907 French physicist P.E., who proposed molecular field theory, extended Lang's theory.
1921 Austrian physicist W. Pauli proposed the Bohr magnetron as the basic single λ of the atomic magnetic moment. American physicist A. Compton proposed that electrons also have spin-corresponding magnetic moments.
1928 British physicist P.A.M. Dirac uses the theory of relativistic quantum mechanics to perfectly explain the intrinsic spin and magnetic moment of electrons. Together with the German physicist W. Heisenberg, it proves the existence of the exchange power of the origin of static electricity and lays the foundation of modern magnetism. In 1936, the Soviet physicist Lang Dao completed the masterpiece "The Course of Theoretical Physics", which contains a comprehensive and wonderful chapter on modern electromagnetics and ferromagnetism.
1936-1948 French physicist L. Neel proposed the concepts and theories of antiferromagnetic and ferrimagnetic, and deepened the understanding of material magnetism in subsequent years of research.
In 1967, Austrian physicist K.J. Snyder discovered a rare earth magnet (SmCo5) with high magnetic energy before the guidance of quantum magnetism, thus opening a new chapter in the development of permanent magnet materials.
In 1967, Strnat et al. of Dayton University in the United States developed a samarium-cobalt magnet, marking the arrival of the era of rare earth magnets.
In 1974, the second generation rare earth permanent magnet-Sm2Co17 was introduced.
1982 third generation rare earth permanent magnet - Nd2Fe14B came out.
1990 atomic gap magnet - Sm-Fe-N came out.
In 1991, German physicist E.F. Kneller proposed the theoretical basis of the exchange function of two-phase composite magnets, pointing out the development prospects of nanocrystalline magnets. Edit the molecular structure of NdFeB