Laboratoire Léon Brillouin
UMR12 CEA-CNRS, Bât. 563 CEA Saclay
91191 Gif sur Yvette Cedex, France
+33-169085241 llb-sec@cea.fr
N. Martin, I. Mirebeau, C. Franz, G. Chaboussant, L. N. Fomicheva, and A. V. Tsvyashchenko
We study the helimagnetic ground state of the MnGe cubic alloy using small-angle neutron scattering and a high-resolution method, the so-called MIEZE spectroscopy. Upon cooling below the Néel temperature TN = 170(5) K, we observe the proliferation of long-wavelength gapless spin fluctuations, concomitant with a continuous evolution of the helical correlation length. These fluctuations disappear at Tcom = 32(5) K when the helical period becomes commensurate with the lattice. We propose to describe this intermediate phase as a soliton lattice, promoting nonlinear collective modes, or phasons, over a large temperature interval. We discuss the possible relevance of our results to the previously observed magnetotransport anomalies.
• Systèmes complexes et transition énergétique › Physique statistique et systèmes complexes
Statistical physics and complex systems
• Laboratoire Léon Brillouin (LLB) • Leon Brillouin Laboratory (LLB)
• Nouvelles frontières dans les matériaux quantiques - NFMQ
• Neutrons • Neutron Spin Precession Spectroscopy • Neutrons • Quasi-elastic scattering