High-field magnetization of Heusler compound Fe2Mn1−xVxSi

Abstract

${\mathrm{Fe}}_{2}\mathrm{MnSi}$ exhibits a ferromagnetic transition at ${T}_{C}\ensuremath{\sim}230$ K and another transition to a phase with antiferromagnetic components at ${T}_{A}\ensuremath{\sim}60$ K. By substituting V for Mn, so as to obtain ${\mathrm{Fe}}_{2}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}\mathrm{Si}$, ${T}_{A}$ is revealed to decrease with $x$ and then vanish around $x\ensuremath{\sim}0.2$. In this study, the phase boundary of the transition at ${T}_{A}$ in the high-field range is found for $0\ensuremath{\le}x\ensuremath{\le}0.15$ with pulsed fields up to $\ensuremath{\sim}70$ T. The magnetization of ${\mathrm{Fe}}_{2}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}\mathrm{Si}$ slowly increases even at the highest field of $\ensuremath{\sim}70$ T, though it occurs more gradually as $x$ increases. We compare the magnetization for $0\ensuremath{\le}x\ensuremath{\le}0.20$ at 62 T with the Slater-Pauling rule, which holds when a Heusler compound is a half-metal, and find fairly good agreement. This suggests an intimate relation between the high-field phase and the half-metallic electronic structure, and that at the high-field limit the phase approaches the half-metallic state, which has been predicted by band-structure calculations.