Why cut open a magnet to get two magnets instead of a unipolar magnet?
The reason why it is not unipolar magnetism is determined by the molecular properties inside the magnet; We all know that when a wire is energized, a series of concentric circular magnetic fields are generated along the wire, and the direction of the magnetic field can be determined using the ampere rule. As for the principle of magnetic field formation in permanent magnets, the Ampere molecular current hypothesis can be used to explain. Since energized wires generate a magnetic field, that is to say, moving electrons will excite a magnetic field in space.
1. Principle of magnetic field formation
Based on this principle, physicist Ampere proposed a hypothesis; He believes that in an atom, electrons outside the nucleus move at high speeds around the nucleus, and the electrons generate an electric current, thus a single atom can generate a magnetic field similar to a bar magnet. But in our daily lives, we cannot perceive the existence of this magnetic field, because in naturally formed objects, the magnetic pole directions between molecules are disorderly, and their magnetic fields cancel out each other and do not show magnetism to the outside; 2. The indivisibility of permanent magnets
However, through some special manufacturing processes, magnets with permanent magnetism can be produced, such as neodymium iron boron magnets, whose chemical formula is Nd2Fe14B; This artificial magnet can arrange the molecules inside the magnet in one direction, forming a magnet with S and N poles. When you cut the magnet from the middle, the internal molecules are not broken, so the surface at the fracture is still intact molecules, and this fracture part is the newly formed complementary pole; That is to say, no matter how many times you cut the magnet, it cannot form a monopole. Therefore, magnetic monopoles do not exist in nature, but scientists are also searching for magnetic monopoles because they are different from traditional magnets; At the same time, magnetic monopole particles are also the choice of dark matter particles in Dark energy; If there is a magnetic monopole, then the study of dark matter will enter a new stage.