Magnetic Viscosity under Discontinuously and Continuously Variable Field Conditions

Abstract

For a ferromagnetic specimen exhibiting magnetic viscosity, the intensity of magnetization increases continuously with time under steady external field conditions An account is given here of investigations to determine the influence on magnetic viscosity of changes in the magnetic field applied to the specimen, two cases of discontinuous and continuous changes in field being considered. The latter case is of practical importance when direct measurements of magnetic viscosity are made using specimens with demagnetization coefficient other than zero since the effective field acting in the specimen is then continuously variable in time. It is found that both cases can be adequately described by extending the previously proposed formal theory of magnetic viscosity in which it was supposed that the domain processes responsible for magnetization can be activated by thermal agitation