MAGNETIC MATERIALS IN RELATION TO STRUCTURE 19 



in two states: one, a solid solution state in which the atoms of iron and 

 nickel are in a disordered distribution; and two, a state in which the 

 iron and nickel atoms are regularly distributed. 



40 50 60 



PER CENT NICKEL 



100 



Fig. 8 



— Effect of heat treatment on initial permeabilities of iron-nickel alloys- 



Elmen". 



In the disordered distribution the lattice points are fixed but the 

 atom positions are not; that is, any lattice point may be occupied by 

 either an iron or nickel atom. In the regular or ordered distribution, 

 the lattice points are fixed and also the atom positions. The second 



