Magnetization and magnetic phase diagram of Heusler compounds Fe3−y (Mn1−x V x ) y Si (y = 1 and 1.5)

Abstract

Fe₂MnSi exhibits a ferromagnetic transition at T_C and another transition to a phase with antiferromagnetic components at a low temperature of T_A . By substituting V for Mn, so as to obtain Fe₂Mn_1−x V _x Si, T_A decreases with x and then vanishes around x ∼ 0.2. In this study, the magnetic transitions are investigated by magnetization measurements for Fe₂Mn_1−x V _x Si (y = 1, 0 ≤ x ≤ 0.2) in high magnetic fields up to ∼70 T and for Fe_1.5(Mn_1−x V _x )_1.5Si (y = 1.5, 0 ≤ x ≤ 0.1) up to 5 T. For y = 1.5, with increasing x, T_C increases and T_A decreases as for y = 1, and the rate of the decrease in T_A with x is slightly smaller than for y=1. In the low magnetic field region, T_A for y = 1 does not significantly change due to the magnetic field but a distinct decrease is observed in high fields. The critical field at 0 K of this transition in Fe₂MnSi is found to be larger than 70 T, and with increasing x, the critical field decreases corresponding to the decrease of T_A at zero field.