A fundamentally new approach to definition of spin magnetic moment of electron is given in this paper. In contrast with the existing descriptions of the spin magnetic moment based on accounting for the interaction of electron with the physical vacuum, it is shown in this paper that the principal component of this moment, i.e. the Bohr magneton, is a property of photon. In a photon decay into an electron and positron a “transfer” of magnetic moment from the photon to the emerging electron-positron pair takes place, which is similar, for example, to “transfer” of the spin from a photon to the emerging electron and positron. It is shown also in this work that the so-called radiative correction to the principal component of the electron spin magnetic moment may be determined by magnetic moments of virtual particles in the virtual particles pair (virtual photon) created by the electron in the physical vacuum. Thus both the principal component of spin magnetic moments of electron (the Bohr magneton) and radiative correction to the principal component are essentially determined by the properties of photons: the photon that has created the electron (in the photon decay into an electron-positron pair) and the virtual photon (the virtual particles pair) created by the electron in the physical vacuum.

spin magnetic moment of electron, virtual particle, photon, magnetism, quantum mechanics