Ferromagnetism of ZrZn2

The magnetic properties of ZrZn2 and related alloys and compounds are discussed. In particular, we present a study of the pseudo-ZrZn2 alloy system ZrCu2−xAlx, where 0.76≤x≤1.5. The results of specific heat, magnetic susceptibility, and nmr measurements are presented to show that the Fermi level of ZrCu1.1Al0.9 lies at the top of a sharp narrow d-band peak that is about 0.1 eV in half-width and has a maximum value of 2.7 states (eV-Zr atom spin)−1. We also show that ZrZn2 has a sharp narrow peak in the d-band density of states at the Fermi level. This peak has a half-width of about 0.05 eV and has a maximum value of 5.4 states (eV-Zr atom spin)−1. The ferromagnetism of ZrZn2 is understandable in terms of this feature of the band structure. The occurrence of a high narrow peak at the Fermi level is the most favorable condition for the existence of itinerant ferromagnetism.