Quasi-two-dimensional magnetism in Cr-based MAX phases

Abstract

The MAX phase is one possible candidate for quasi-two-dimensional (Q2D) magnets owing to its layered structure. We report itinerant electron ferromagnetic and antiferromagnetic long-range orders in (Cr1-xMn x )2GeC and Cr2GaN, respectively. Because Cr2GaN orders in a spin-density-wave state, the Q2D character is highly plausible. However, the Q2D nature is not straightforward in (Cr1-xMn x )2GeC because of the absence of useful criteria to judge the dimensionality in the itinerant electron ferromagnet. In this article, we attempt to reveal the Q2D character of ferromagnetic (Cr1-xMn x )2GeC by analyzing magnetic data in terms of the spin fluctuation theory for the Q2D system.