A Study of Magnetic Viscosity

A general analysis of magnetic viscosity based on activation energy concepts is given. A particular case is considered of the application of the theory to the phenomenon occurring in materials in which bulk magnetization proceeds by the rotational movement of the vectors of single domains, which process, according to a recent theory of Stoner and Wohlfarth, may occur in certain high coercivity alloys. Experiments have been made, using a magnetometer method, with specimens of alnico maintained at various temperatures within the range - 187° c. to 250° c. The results obtained are found to be in good agreement with the theoretical analysis.