Itinerant electron magnetism of hexagonal La₂Ni₇

Magnetizations of itinerant electron magnets La₂Ni₇ and related compounds with a hexagonal crystal structure were measured. Successive metamagnetic transitions were observed in La₂Ni₇, and H-T phase diagram of La₂Ni₇ was determined. The zero-field state may be antiferromagnetic for T < T_t1 = 54 K, and is a state of some kind (probably antiferromagnetic) with a very small ferromagnetic moment in T_t1 < T < T_t2 = 66 K. Substitutions of Co or Cu for Ni show that the band structure of La₂Ni₇ tends to produce both ferromagnetic and antiferromagnetic states, favoring the application of the theory of Moriya and Usami. Their theory is applicable assuming a tendency to form two types of antiferromagnetic states and a tendency to form a ferromagnetic state.