Magnetic Fluctuations, Precursor Phenomena, and Phase Transition in MnSi under a Magnetic Field

Journal Article (2017)
Author(s)

C. Pappas (TU Delft - RST/Neutron and Positron Methods in Materials)

Lars Bannenberg (TU Delft - RST/Neutron and Positron Methods in Materials)

E. Lelievre-Berna (Institut Laue Langevin)

F. Qian (TU Delft - RST/Neutron and Positron Methods in Materials)

C. D. Dewhurst (Institut Laue Langevin)

Robert M. Dalgliesh (Rutherford Appleton Laboratory)

D. L. Schlagel (Iowa State University)

T. A. Lograsso (Iowa State University)

P Falus (Institut Laue Langevin)

Research Group
RST/Neutron and Positron Methods in Materials
Copyright
© 2017 C. Pappas, L.J. Bannenberg, E. Lelièvre-Berna, F. Qian, C. D. Dewhurst, R. M. Dalgliesh, D. L. Schlagel, T. A. Lograsso, P Falus
DOI related publication
https://doi.org/10.1103/PhysRevLett.119.047203
More Info
expand_more
Publication Year
2017
Language
English
Copyright
© 2017 C. Pappas, L.J. Bannenberg, E. Lelièvre-Berna, F. Qian, C. D. Dewhurst, R. M. Dalgliesh, D. L. Schlagel, T. A. Lograsso, P Falus
Research Group
RST/Neutron and Positron Methods in Materials
Issue number
4
Volume number
119
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

The reference chiral helimagnet MnSi is the first system where Skyrmion lattice correlations have been reported. At a zero magnetic field the transition at TC to the helimagnetic state is of first order. Above TC, in a region dominated by precursor phenomena, neutron scattering shows the buildup of strong chiral fluctuating correlations over the surface of a sphere with radius 2π/, where is the pitch of the helix. It has been suggested that these fluctuating correlations drive the helical transition to first order following a scenario proposed by Brazovskii for liquid crystals. We present a comprehensive neutron scattering study under magnetic fields, which provides evidence that this is not the case. The sharp first order transition persists for magnetic fields up to 0.4 T whereas the fluctuating correlations weaken and start to concentrate along the field direction already above 0.2 T. Our results thus disconnect the first order nature of the transition from the precursor fluctuating correlations. They also show no indication for a tricritical point, where the first order transition crosses over to second order with increasing magnetic field. In this light, the nature of the first order helical transition and the precursor phenomena above TC, both of general relevance to chiral magnetism, remain an open question.

Files

PhysRevLett.119.047203.pdf
(pdf | 1.45 Mb)
License info not available