Magnetic properties of single crystalline Mn4Si7

A single crystal of MnSi2-x was obtained by a modified Czochralski pulling technique in a cold copper crucible. The quality and the nature of the sample were checked by an accurate crystal structure determination, which revealed the sample to be Mn4Si7. Resistivity and magnetic measurements were performed on this sample in the temperature range between 2 K and room temperature and in magnetic fields up to 7.5 T. Mn4Si7 shows a metallic behaviour and the good crystal quality was revealed by the high residual resistance ratio of 360. For the magnetic susceptibility we observed a Curie-Weiss law above about 40 K with a low effective moment of peff=0.365 μB/Mn. Below this temperature, moments order in an anisotropic helical state, and in fields above 1 T, they align with a saturation moment of psat=0.012 μB/Mn. Mn4Si7 is a weak itinerant magnetic system that could be a good candidate for the observation of the critical quantum fluctuations expected for marginal Fermi liquids