4 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1952 



ill a paper which gives a very satisfying physical model with which to 

 mterpret gyromagnetic phenomena occurring within ferrites. 



Physical analysis indicates that the properties of ferromagnetic 

 materials can be explained by assuming that the electron behaves as if 

 it were a negatively charged sphere which is spinning about its own 

 axis wdth a fixed angular momentum. This rotation of charge imparts 

 to the electron a magnetic moment which is a function of the electric 

 charge on the electron, the angular velocity of the electron, and its 

 size. Thus the electron behaves as if it were a spinning magnetic top, 

 whose magnetic moment lies along the axis of rotation, and its behavior 

 can be understood by considering a spinning gyroscope suspended in 

 gimbal rings at a point not coinciding with its center of gra^dty. If a 

 gyroscope, thus supported in a gravitational field, is lifted away from 

 its position of minimum potential energy and then released, it wall not 

 return to the position of minimum energy but \\dll precess about the 

 vertical axis. This is illustrated in Fig. 2 where the spinning gyroscope 

 makes an angle d with the vertical 0, axis. Its equilibrium motion, in 

 the absence of damping, is a precessional motion about the vertical 

 axis with a velocity cop. 



If the gyTOSCope be regarded as initially hanging vertically downward 



X X 



Fig. 2 (left) — Precessional motion of a gjToscopic pendulum in a gravitational 

 field. Fig. 3 (right) — Precessional motion of a gyroscopic pendulum in a gravita- 

 tional field which oscillates between the directions A and B. 



