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BELL SYSTEM TECHNICAL JOURNAL 



9, means that at all temperatures below 6 the intensity of magnetization 

 has a definite value even when no field is applied. 



How is it then that a piece of iron can apparently be unmagnetized 

 at room temperature? The answer, given by Weiss, is that below the 

 Curie point all parts of the iron are magnetized to saturation but that 

 different parts are magnetized in different directions so that the overall 



1.0 



0.9 



Z 0.7 



o 



0.6 



0.5 



a. 0.4 



II 



i/5| O 



0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 



X 



e 



Fig. 9 — Dependence on the temperature of the saturation magnetization 

 of iron, cobalt and nickel, as compared with theory. 



effect is zero. This is the concept of the domain, already discussed. 

 According to this conception the / of Eq. (5) is that of a domain and is 

 determined experimentally by measuring the magnetization of a 

 specimen when all domains are parallel, i.e., at (technical) saturation 

 (/ = It). Eq. (6) should then be written 



