Magnetic phases in single crystals Mn5Si3

R.F. LUCCAS; A. CORREA-ORELLANA; F. J. MOMPEAN; M. GARCÍA- HERNANDEZ; S. VIEIRA; H. SUDEROW

Barcelona

Congreso; 20th International Conference on Magnetism ICM2015; 2015

Transition metal magnets arecharacterized by having moments strongly linked to their local environment.This leads to a rich interplay between d-electron magnetism andnearest-neighbor interactions.[1] Topological non-trivial arrangement, likeskyrmions in MnSi, have been trust important for developing new devices,however the Mn-Si family have been not extensively studied. In particular, previousneutron scattering in polycrystalline or powder samples of Mn5Si3 show severalmagnetic phases, with two magnetic transitions TN1 = 60 K and TN2 = 90 K. BelowTN1, spins are arranged in a non-collinear structure, showing local chirality.This phase is destroyed by a magnetic field of several Tesla, favoring the hightemperature antiferromagnetic arrangement.[2]In this work, a study of thephase diagram of the Mn5Si3 system is presented. Crystals of Mn5Si3 were grown outof Cu flux. Needles with typically 6 mm in length and a non-regular octagonal crosssection of about 1 mm2 were obtained. Magnetization measurements up to 7 T anddown to 2 K were performed on individual needles along their main axis. Knownmagnetic transitions TN1 and TN2 were observed in combination with a new additionaltransition TN1* at 45 K. TN1 was observed magnetic field independent, whereas TN1*strongly decreases with the magnetic field. In addition, several transitionwere observed for the phase down TN1* when increasing field at a fixedtemperature. Our measurements suggest that the low temperature magneticnon-collinear structure unwinds with the magnetic field through metamagnetictransitions. There is an additional intermediate magnetic phase between 45 Kand 60 K, which is probably also non-collinear. The role of sample synthesis onthe magnetic structure is briefly discussed.[1] Naoto Nagaosa and Yoshinori Tokura, Nature Nanotechnology 8, 899 (2013).[2] Christoph Surgers, et al., Nature Communications 5, 3400 (2014).