Magnetic phase transition in (Mn 0.95Ni 0.05) 3B 4

It was found that the metallic compound (Mn _0.95Ni _0.05) ₃B ₄ was ferromagnetic below 195 K and antiferromagnetic between 195 and 354 K. The transition temperature from ferromagnetic to antiferromagnetic increases with increasing external magnetic field. On the other hand, the transition temperature from antiferromagnetic to paramagnetic decreases with increasing magnetic field. It is expected that the present results might be explained by the theoretical results on the coexistence of ferro- and antiferromagnetism in the itinerant electron system reported by Moriya and Usami.