Natural magnets discovered 5,000 years ago (Fe3O4)
2,300 years ago, the Chinese people ground natural magnets into spoons and placed them on a smooth surface. Under the influence of geomagnetic forces, the guide for spoon handles, called "Si Nan", was the world's first guide instrument.
About 1000 years ago, the Chinese made the world's first compass by rubbing an iron needle with a magnet.
Around 1100, the Chinese combined the magnet needle with the azimuth plate into a magnet guide for navigation.
Zheng He started his great feats of navigation in human history with his guidebook.
Columbus, Gama, and Magellan made world-famous voyages using the compass.
1600An Englishman, William Gibb, published his monograph on magnetism, "The Magnet", which developed the understanding and experiments of the ancient Greeks, Such as Thales and Aristotle, on magnetism.
In 1785, The French physicist C. Coulomb's law, which describes the interaction between charge and magnetic pole, was established by means of a torsion balance.
The 1820 Danish physicist H.C. Oster discovered electromagnetics.
1831 M. Faraday, British physicist, discovered electromagnetic induction.
In 1873 the British physicist J.C. Maxwell completed the unified theory of electromagnetism in his monograph "On Electricity and Magnetism."
French physicist P. Curie discovered that ferromagnetic materials become paramagnetic at a certain temperature (Curie temperature).
1905 French physicist P.I. Langevin explained the change of paramagnetism with temperature based on statistical mechanics theory.
The French physicist P.E. Weiss, in 1907, developed the theory of the molecular field.
1921 The Austrian physicist W. Pauli proposed the Bohr magneton as the basic unit of atomic magnetic moment.
American physicist A. Compton proposed that electrons also have magnetic moments corresponding to their spins.
In 1928 the British physicist P.A.M. Dirac perfectly explained the intrinsic spin and magnetic moment of electrons in relativistic quantum mechanics.
Together with The German physicist W. Heisenberg, they proved the existence of exchange forces in the origin of static electricity, which laid the foundation of modern magnetism.
In 1936, The Soviet physicist Langdao completed his great "Course in Theoretical Physics", which contains a comprehensive and wonderful exposition of modern electromagnetism and ferromagnetism.
1936-1948 French physicist L. Nair put forward the concept and theory of antiferromagnetism and ferromagnetism, and deepened the understanding of material magnetism in the following years of research.
In 1967, an Austrian physicist in the United States, K.J. Snart, discovered the highest level of magnetic energy under the guidance of quantum magnetism
Rare earth magnet (SmCo5) opens a new chapter in the development of permanent magnet materials.
In 1967, Strnat et al. of the University of Dayton, United States, developed a samarium cobalt magnet, marking the arrival of the era of rare earth magnets.
1974 The second generation of rare earth permanent magnet -Sm2Co17 was introduced.
1982 Masato Sagawa of Japan invented ndfeb magnet and Nd2Fe14B, the third generation of rare earth permanent magnet, was introduced.
1990 Atomic gap magnet -Sm-Fe-N was introduced.
In 1991, German physicist E.F. Knoller proposed the theoretical basis for the exchange of dual phase composite magnets and pointed out the development prospect of nanocrystalline magnets.
With the development of society, the application of magnets has become more and more extensive, from high-tech products to the simplest packing magnets,
At present, the most widely used or neodymium iron boron magnet and ferrite magnet. From the development history of magnets, in the late 19th century and early 20th century, people mainly used carbon steel, tungsten steel, chromium steel and cobalt steel as permanent magnetic materials. The development of aluminum-nickel-cobalt magnets in the late 1930s made large-scale use of magnets possible.
In the 1950s, the emergence of barium ferrite magnets not only reduced the cost of permanent magnets, but also extended the application range of permanent magnet materials to the field of high frequency.
In the 1960s, the appearance of samarium cobalt permanent magnet opened up a new era for the application of magnet.
So far, rare earth permanent magnetic materials have experienced the first generation of SmCo5, the second generation of precipitation hardening Sm2Co17, and the third generation of ND-FE-B permanent magnetic materials.
At present, ferrite magnet is still the largest permanent magnet material, but the output value of NdFeb magnet has greatly exceeded that of ferrite permanent magnet. The production of NdFeb magnet has developed into a big industry.