Energy Changes Accompanying Magnetization

Abstract

IT is generally stated that the heat evolved in a hysteresis cycle is given by the expression HdI, where I is the intensity of magnetization of a ferromagnetic specimen in an effective field H, although it is very difficult to provide an adequate proof of this statement. In recent years several attempts have been made to investigate the heat liberated or absorbed when a ferromagnetic is taken through the several stages of a single hysteresis cycle step-by-step. Thus, Adelsberger¹ found that the total quantity of heat liberated by unit volume of a hard steel in a single complete cycle is equal to that calculated from ^{+ H}_HHdI, and so provided a proof of what is known as Warburg's Law.