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Univ. Paris-Saclay
23 octobre 2019
Partial ordering and phase elasticity in the MnGe short-period helimagnet
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Partial ordering and phase elasticity in the MnGe short-period helimagnet

Temperature dependence of the soliton velocity

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.

https://doi.org/10.1103/PhysRevB.99.100402

 
#3168 - Màj : 23/10/2019

 

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