Gyromagnetic Effect in Some Ferromagnetic Powders

Abstract

BOTH the gyromagnetic effects, namely, the production of (1) magnetisation by rotation, and of (2) rotation by magnetisation, have been applied to deduce the ratio of angular momentum to magnetic moment of the elementary magnet in ferromagnetics. The theoretical value of this ratio R for an orbital electron is 2m/e and for a spinning electron m/e. Results of observations on all ferromagnetics by the method of rotation by magnetisation gave values¹ of R exactly equal to m/e within very narrow limits of experimental error, which is less than one per cent for the metallic rods, and about five per cent for the powders investigated. Making use of the first effect, Barnett² found for the ferromagnetic metals values of R which, according to his estimate, are several per cent higher than the orthodox value for the spinning electron. This may mean that the orbital moment is also partly effective in producing ferromagnetism.