Preparation and structural characterization of ferromagneticMn5Si3C

Abstract

Si films prepared by magnetron sputtering at elevated substrate temperatures exhibit ferromagnetic order for compositions around Mn 5 Si 3 C x (xϾ0) in contrast to the antiferromagnetic Mn 5 Si 3 compound. In these sputtered samples the carbon concentration can be strongly enhanced compared to sintered powder samples. The local structural order around the Mn site in Mn 5 Si 3 C x films was investigated for xϭ0 and 0.75 by x-ray-absorption spectroscopy at different temperatures T. At low T, both films retain their hexagonal structure and do not exhibit the orthorhombic distortion observed for bulk Mn 5 Si 3 powder. For the carbon-doped film a local distortion of the octahedra formed by six Mn atoms of the Mn 5 Si 3 structure is found when surrounding a C atom. This indicates an anisotropic change of the atomic Mn environment by C, in contrast to a simple lattice expansion as inferred from previous structural analysis.

Large topological Hall effect in the non-collinear phase of an antiferromagnet

“…This supports our conclusion that the additional contribution to the AHE attributed to a THE in antiferromagnetic Mn 5 Si 3 arises from the non-collinear magnetic structure in the AF1 phase. ð Þ-oriented sapphire substrates (thickness 0.53 mm) at a substrate temperature T S ¼ 470°C and were characterized by X-ray diffraction to confirm formation of the Mn 5 Si 3 -type structure 26,31 . The films have a coarsely grained morphology with an average grain size equal to the film thickness 31 .…”

Simulation of the enhanced Curie temperature in Mn5Ge3Cx compounds

“…3 It was shown 3 that carbon incorporation into the octahedral voids of the hexagonal Mn 5 Ge 3 cell leads to a continuous increase of T C with the doping level in Mn 5 Ge 3 C x and suggests a saturation when all octahedral voids are filled by carbon. A maximum T C of 445 K was obtained for Mn 5 Ge 3 C 0.8 films, obtained by magnetron sputtering. The carbon implanted Mn 5 Ge 3 C 0.8 films were found to exhibit magnetic properties very similar to their sputtered counterparts.…”

“…Mavropoulos, 2 5 Ge 3 C x films with x Ն 0.5 were experimentally shown to exhibit a strongly enhanced Curie temperature T C compared to Mn 5 Ge 3 . In this letter we present the results of our first principles calculations within Green's function approach, focusing on the effect of carbon doping on the electronic and magnetic properties of the Mn 5 Ge 3 .…”

“…4 At the same time, the isostructural antiferromagnetic ͑AFM͒ Mn 5 Si 3 with T N = 98 K was reported to exhibit ferromagnetism when doped with carbon, with the transition temperature reaching 350 K in Mn 5 Si 3 C 0.8 . 5 While in Mn 5 Si 3 C x films the interstitial carbon leads to a lattice expansion, the increase of T C upon doping in Mn 5 Ge 3 C x is accompanied by a lattice compression. 3 However, it was suggested that the observed lattice distortions in both Mn 5 Ge 3 C x and Mn 5 Si 3 C x can have a very small influence on the increase of the transition temperatures.…”

“…Among them, Mn 5 Ge 3 seems to be a promising candidate due to its compatibility with mainstream silicon technology. 1 The low Curie temperature ͓T C = 304 K ͑Ref.…”