Universality of the helimagnetic transition in cubic chiral magnets: Small angle neutron scattering and neutron spin echo spectroscopy studies of Fe${}_{1-x}$Co${}_x$Si

Abstract

We present a comprehensive Small Angle Neutron Scattering (SANS) and Neutron Spin Echo Spectroscopy (NSE) study of the structural and dynamical aspects of the helimagnetic transition in Fe${}_{1-x}$Co${}_x$Si with $x$ = 0.30. In contrast to the sharp transition observed in the archetype chiral magnet MnSi, the transition in Fe${}_{1-x}$Co${}_x$Si is gradual and long-range helimagnetic ordering coexists with short-range correlations over a wide temperature range. The dynamics are more complex than in MnSi and involve long relaxation times with a stretched exponential relaxation which persists even under magnetic field. These results in conjunction with an analysis of the hierarchy of the relevant length scales show that the helimagnetic transition in Fe${}_{1-x}$Co${}_x$Si differs substantially from the transition in MnSi and question the validity of a universal approach to the helimagnetic transition in chiral magnets.

References in corpus (19)

• Skyrmion Lattice in a Chiral Magnet
• Spontaneous Skyrmion Ground States in Magnetic Metals
• Skyrmion Lattice in a Doped Semiconductor
• Long wavelength helimagnetic order and skyrmion lattice phase in Cu2OSeO3
• Precursor phenomena at the magnetic ordering of the cubic helimagnet FeGe
• Fluctuation-induced first-order phase transition in Dzyaloshinskii-Moriya helimagnets
• Topological stability versus thermal agitation in a metastable magnetic skyrmion lattice
• Specific heat of the skyrmion lattice phase and field-induced tricritical point in MnSi
• Confinement of Chiral Magnetic Modulations in the Precursor Region of FeGe
• History dependence of the magnetic properties of single-crystal Fe${}_{1-x}$Co${}_x$Si
• Critical scaling in a cubic helimagnet Cu2OSeO3
• The Dzyaloshinskii-Moriya interaction is under control: an orchestrated flip of the chiral link between structure and magnetism for Fe${}_{1-x}$Co${}_x$Si
• Ultrasonic studies of the magnetic phase transition in MnSi
• Magnetic relaxation phenomena in the Chiral Magnet Fe${}_{1-x}$Co${}_x$Si: An ac susceptibility study
• Magnetic Fluctuations and Correlations in MnSi - Evidence for a Skyrmion Spin Liquid Phase
• Comparative study of helimagnets MnSi and Cu2OSeO3 at high pressures
• Extended skyrmion lattice scattering and long-time memory in the chiral magnet Fe${}_{1-x}$Co${}_x$Si
• Smectic to nematic transition of magnetic texture in conical state
• Notes on the Vollhardt "invariant" and phase transition in the helical itinerant magnet MnSi

Cited by in corpus (9)

• Magnetic Fluctuations, Precursor Phenomena and Phase Transition in MnSi under Magnetic Field
• Skyrmions and spirals in MnSi under hydrostatic pressure
• Metamagnetic transitions and magnetoelectric responses in a chiral polar helimagnet Ni${}_2$InSbO${}_6$
• Increasing the skyrmion stability in Cu${}_2$OSeO${}_3$ by chemical substitution
• Skyrmion-Excited Spin Wave Fractal Network
• Formation of incommensurate long-range magnetic order in the Dzyaloshinskii-Moriya antiferromagnet Ba${}_2$CuGe${}_2$O${}_7$ studied by neutron diffraction
• Evolution of Helimagnetic Correlations when approaching the Quantum Critical Point of Mn${}_{1-x}$Fe${}_x$Si
• Entropic signatures of the skyrmion lattice phase in MnSi1-xAlx and Fe1-yCoySi
• Spin Excitation in Coupled Honeycomb Lattice Ni${}_2$InSbO${}_6$