In atomic physics, the Bohr magneton (symbol μB) is a physical constant and the natural unit for expressing the magnetic moment of an electron caused by its orbital or spin angular momentum.
where The idea of elementary magnets is due to Walther Ritz (1907) and Pierre Weiss.
Already before the Rutherford model of atomic structure, several theorists commented that the magneton should involve the Planck constant h.[6] By postulating that the ratio of electron kinetic energy to orbital frequency should be equal to h, Richard Gans computed a value that was twice as large as the Bohr magneton in September 1911.
[7] At the First Solvay Conference in November that year, Paul Langevin obtained a value of
[8] Langevin assumed that the attractive force was inversely proportional to distance to the power
[9] The Romanian physicist Ștefan Procopiu had obtained the expression for the magnetic moment of the electron in 1913.
First, the orbital motion of an electron around a nucleus generates a magnetic moment by Ampère's circuital law.
In the Bohr model of the atom, for an electron that is in the orbit of lowest energy, its orbital angular momentum has magnitude equal to the reduced Planck constant, denoted ħ.
The Bohr magneton is the magnitude of the magnetic dipole moment of an electron orbiting an atom with this angular momentum.