CI. Magnetic properties of nickel-cobalt and related alloys

Summary A discussion is given, on the basis of the collective electron theoretical treatment of ferromagnetism, of the magnetic properties of nickel-cobalt and related alloys. In §1 previous work and the main underlying assumptions are briefly discussed in relation to the present work. Experimental results for nickel-cobalt and nickel-iron alloys, shown in §2 in a number of figures, include the variation of the saturation moment, σ0, and Curie temperature, ϑ, with concentration, c, and of the susceptibility and spontaneous magnetization with temperature. In fig. 5 values of ϑ derived theoretically (from the variation of σ0 with c) are compared with observed values, and good general agreement is found, although there are significant deviations, more pronounced for nickel-iron. Reduced magnetization, temperature curves for nickel-cobalt obey the “ law of corresponding states ”, but those for nickel-copper do not; they tend to approach the collective electron theoretical curve as the copper concentration increases (fig. 7).