Mn-doping-induced itinerant-electron ferromagnetism in Cr2GeC

The magnetism of the M(n+1)AX(n) phase, Cr2GeC, and its Mn-doped system, (Cr1-xMnx)(2)GeC (x <= 0.25), synthesized via a solid state reaction, was investigated systematically. Cr2GeC is in a spin-unpolarized state, but the ferromagnetic band polarization is induced immediately by the Mn doping. The Curie temperature, T-C, and the spontaneous moment, p(s), increase almost proportionally to the Mn concentration, strongly suggesting that Cr2GeC 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 (CrGeC)-Ge-2 can be classified as a typical itinerant-electron ferromagnetism in a wide range of the degree of electron localization.