Mathon plots

The magnetic phase diagram for the Co system is shown in fig. 25 and table 13 lists the important properties. The ferromagnetic alloys are regarded as itinerant because of the linearity of the Arrott plots over a wide range of temperature and also of the Mathon plots of M02 as a function of x (Hilscher and Kirchmayr 1975). Calculations of the density of states (Terao and Shimizu 1983) show that the itinerant-electron model gives a volume magnetostriction consistent with the experimental value (Muraoka et al. 1980, 1983). 

Plots of Tc and Mo versus concentration x (Mathon plots) show a linear relationship for x > 0.7. Resistivity measurements (Gratz and Kirchmayr, 1976) also support this picture. 

Fig. 3.20 Plot of A (in Ap=AT2) against Ni concentration in Pd-Ni (Tari and Coles 1971). The index n in T" is shown. Note that Mathon (1968) predicted n near the peak.

From eq. (14.23) one obtains a quadratic temperature dependence of the reciprocal susceptibility and a linear dependence of versus HIM over a large temperature region (so-called Arrott plots). Mathon discussed the concentration dependence of Af(0,0), Tc and yo by using the Landau theory for weak ferromagnets in the critical region. There exists a close analogy between what happens for a fixed concentration when the temperature is varied and what happens for a fixed temperature when the concentration is varied A T, x) =... 

---