Magnetic properties of fcc and ? phases in equiatomic and off-equiatomic high-entropy Cantor alloys

Abstract

The equiatomic face-centered-cubic (fcc) high-entropy alloy CrMnFeCoNi has a valence electron concentra-tion of 8 electrons per atom, equivalent to that of Fe. Its ground-state properties are similar to that of fcc-Fe and exhibits the anti-Invar effect at finite temperatures. It additionally exhibits various magnetic interactions at low temperatures which are not fully understood. To resolve this, we prepare and investigate the magnetic and structural properties of off-equiatomic Cr20+xMn20Fe20Co20Ni20-x high-entropy alloys with 0 x 20 at.% by making use of the composition-dependent transformation from the fcc to the a phase with increasing x. We employ x-ray diffraction, scanning electron microscopy, magnetization, and microhardness studies. The results suggest that these alloys order antiferromagnetically around 75-90 K before entering into a spin-frozen state below 40 K.