Stress-induced magnetic textures and fluctuating chiral phase in MnGe chiral magnet

M Deutsch (1) , Pierre Bonville (2) , A. V. Tsvyashchenko (3, 4) , L. N. Fomicheva (4) , F. Porcher (1) , F. Damay (1) , S. Petit (1) , Isabelle Mirebeau (1)

1 LLB - UMR 12 - Laboratoire Léon Brillouin
2 LNO - Laboratoire Nano-Magnétisme et Oxydes
3 SINP - D.V. Skobeltsyn Institute of Nuclear Physics
4 RAS - Russian Academy of Sciences [Moscow]

We have studied the MnGe chiral magnet below T N = 170 K, by magnetic measurements, Mössbauer spectroscopy, and by neutron diffraction at ambient and under nonhydrostatic pressure. At ambient pressure, we observe the coexistence of two magnetic phases belonging to the same crystal phase in a large temperature range (down to 100 K) below T N : ferromagnetically correlated rapidly fluctuating spins coexist with frozen spins involved in the helical order. Applying a uniaxial pressure component induces a strong magnetic texture, where most of the helical axes reorient along the stress axis. The magnetic texture persists in the fluctuating chiral state up to T N. Our results suggest that the zero field ground state at ambient pressure is a multidomain state consisting of helical domains with random orientations rather than a three-dimensional skyrmion lattice. They show the presence of an unusually broad transition to paramagnetism with a dynamical phase separation triggered by temperature.

Domains: Physics [physics]

M Deutsch, Pierre Bonville, A. V. Tsvyashchenko, L. N. Fomicheva, F. Porcher, et al.. Stress-induced magnetic textures and fluctuating chiral phase in MnGe chiral magnet. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 90, pp.144401. ⟨10.1103/PhysRevB.90.144401⟩. ⟨cea-01377039⟩