TRIUMF

Exp. No.

M1744 — Approved

Title of Experiment

Study of topological critical behavior in MnGe

Spokesperson(s) for Group

Safety Coordinator(s) for Group

Current Members of Group

Name Institution Status % of research time devoted to experiment
Z. Guguchia Columbia University Research Scientist
G.M. Luke McMaster University Professor
Y.J. Uemura Columbia University Professor
Z. Gong Columbia University Student (PhD)
J. Beare McMaster University Student (PhD)
Y. Cai McMaster University Student (PhD)
S.C. Cheung Columbia University Student (PhD)
B. Frandsen University of California, Berkeley PDF
A.M. Hallas McMaster University Student (PhD)
N. Kanazawa U. Tokyo Assistant Professor
T. Munsie McMaster University Student (PhD)
Naoto Nagaosa University of Tokyo Professor
Y. Tokura JRCAT/University of Tokyo Professor
M.N. Wilson McMaster University Student (PhD)

Abstract

We propose the direct observation of magnetic critical phenomena by 1/T1 MuSR measurements in MnGe under external field. With the field points measured so far (0T, 0.5T, 3T, 5T), significant field-dependence of the 1/T1 critical behavior is identified. Furthermore, the shape of the 1/T1 peak changes from highly asymmetric to symmetric as the field increases from 0 to 5T. We’ve also identified quadratic dependence on temperature of the 1/T1 relaxation rate. This is quite different from the linear-T behavior found in MnSi. The contrasting behaviors between MnSi and MnGe indicate that the Korringa process is dominant in the itinerant electron weak magnet MnSi, while a spin-wave process plays more significant role in MnGe. This observation is consistent with the fact that MnGe is a metallic system but is a much stronger magnet compared to MnSi. To further elucidate the above novel observations, additional measurements in zero-field and at different applied fields are required.