The magnetic moment is the fundamental property of elementary particles

The magnetic moment of an atom is the basic physical vector quantity that characterizes the magnetic properties of any substances. The source of the formation of magnetism, as the classical electromagnetic theory maintains, are microcurrents arising from the motion of an electron in orbit. The magnetic moment is an indispensable property of all elementary particles, nuclei, atomic electronic shells and molecules without exception.

Magnetism, which is inherent in all elementary particles, according to quantum mechanics, is due to the presence of a mechanical moment called a spin (its own mechanical momentum of quantum nature). The magnetic properties of the atomic nucleus are composed of spin impulses of the constituent parts of the nucleus - protons and neutrons. Electronic shells (intra-atomic orbits) also have a magnetic moment, which is the sum of the magnetic moments of electrons on it.

In other words, the magnetic moments of elementary particles and atomic orbitals are due to the intra-atomic quantum-mechanical effect, known as the spin pulse. This effect is similar to the angular momentum of rotation around its own central axis. The spin pulse is measured in the Planck constant, the basic constant of the quantum theory.

All neutrons, electrons and protons, of which, in fact, the atom consists, according to Planck, have a spin equal to ½. In the structure of an atom, electrons, rotating around the nucleus, in addition to the spin pulse, also have an orbital angular momentum. The nucleus, although it occupies a static position, also has an angular momentum, which is created by the effect of the nuclear spin.

The magnetic field that generates an atomic magnetic moment is determined by the different forms of this angular momentum. The most noticeable contribution to the creation of a magnetic field is made by the spin effect. According to the Pauli principle, according to which two identical electrons can not be simultaneously in the same quantum state, the bound electrons merge, and their spin impulses acquire diametrically opposite projections. In this case, the magnetic moment of the electron is reduced, which reduces the magnetic properties of the entire structure. In some elements that have an even number of electrons, this moment decreases to zero, and the substances cease to possess magnetic properties. Thus, the magnetic moment of individual elementary particles has a direct effect on the magnetic qualities of the entire nuclear-atomic system.

Ferromagnetic elements with an odd number of electrons will always have nonzero magnetism due to the unpaired electron. In such elements, neighboring orbitals overlap, and all the spin moments of unpaired electrons assume the same orientation in space, which leads to the attainment of the lowest energy state. This process is called the exchange interaction.

With this equalization of the magnetic moments of ferromagnetic atoms, a magnetic field arises. And paramagnetic elements, consisting of atoms with disoriented magnetic moments, do not have an intrinsic magnetic field. But if we act on them by an external source of magnetism, then the magnetic moments of the atoms will equalize, and these elements will also acquire magnetic properties.