Ionicity trends in the diamagnetism and its temperature dependence in average-valence-four semiconductors

Measurements are reported of the magnetic susceptibility $\chi$, and its temperature coefficient $\frac{d\chi }{\mathrm{dT}}$ for 13 alkali halides and for InP, ZnS, ZnSe, CdTe, MgS, and MgO. Although clear ionicity trends are observed, the results reveal substantial deficiencies in present chemical-bond theories of the diamagnetism of average-valence-four semiconductors. In addition it has been observed that $\frac{d\chi }{\mathrm{dT}}$ appears sensitive to mechanical damage for the more ionic materials in a way which is not presently understood.