Mn-doping-induced itinerant-electron ferromagnetism in Cr[2]GeC

Abstract

The magnetism of the M[n+1]AXn phase, Cr[2]GeC, and its Mn-doped system, (Cr[1−x]Mn[x])[2]GeC (x≤0.25), synthesized via a solid state reaction, was investigated systematically. Cr[2]GeC is in a spin-unpolarized state, but the ferromagnetic band polarization is induced immediately by the Mn doping. The Curie temperature, TC, and the spontaneous moment, ps, increase almost proportionally to the Mn concentration, strongly suggesting that Cr[2]GeC is located in the vicinity of a ferromagnetic quantum critical point. The strong concentration dependence of p[eff]/p[s], where p[eff] is the effective moment in the paramagnetic state, indicates that the ferromagnetism appearing in the Mn-doped Cr[2]GeC can be classified as a typical itinerant-electron ferromagnetism in a wide range of the degree of electron localization.