Understanding the H-T phase diagram of the mono-axial helimagnet

Abstract

Some unexpected features of the phase diagram of the monoaxial helimagnet in presence of an applied magnetic field perpendicular to the chiral axis are theoretically predicted. A rather general hamiltonian with long range Heisenberg exchange and Dzyaloshinskii--Moriya interactions is considered. The continuum limit simplifies the free energy, which contains only a few parameters which in principle are determined by the many parameters of the hamiltonian, although in practice they may be tuned to fit the experiments. The phase diagram contains a Chiral Soliton Lattice phase and a forced ferromagnetic phase separated by a line of phase transitions, which are of second order at low T and of first order in the vicinity of the zero-field ordering temperature, and are separated by a tricritical point. A highly non linear Chiral Soliton Lattice, in which many harmonics contribute appreciably to the spatial modulation of the local magnetic moment, develops only below the tricritical temperature, and in this case the scaling shows a logarithmic behaviour similar to that at T=0, which is a universal feature of the Chiral Soliton Lattice. Below the tricritical temperature, the normalized soliton density curves are found to be independent of T, in agreement with the experimental results of magnetorresistance curves, while above the tricritical temperature they show a noticeable temperature dependence. The implications in the interpretation of experimental results of CrNb3S6 are discussed.

11 pages, 17 figures. Enlarged version, with more details and results. To be publisehd in Phys. Rev. B

References in corpus (4)

• Finite-Temperature Properties of Three-Dimensional Classical Chiral Helimagnets
• Spin Structure of the Anisotropic Helimagnet Cr${}_{1/3}$NbS${}_2$ in a Magnetic Field
• Incommensurate--commensurate transitions in the mono-axial chiral helimagnet driven by the magnetic field
• Phase transitions and ordering structures of a model of chiral helimagnet in three dimensions

Cited by in corpus (16)

• Tricritical point and phase diagram based on critical scaling in monoaxial chiral helimagnet Cr1/3NbS2
• Crossover of skyrmion and helical modulations in noncentrosymmetric ferromagnets
• Order and Disorder in the Magnetisation of the Chiral Crystal CrNb${}_3$S${}_6$
• Nucleation, instability, and discontinuous phase transitions in monoaxial helimagnets with oblique fields
• Magnetic field dependence of the nonlinear magnetic response and tricritical point in the monoaxial chiral helimagnet Cr${}_{1/3}$NbS${}_2$
• Stability of skyrmion textures and the role of thermal fluctuations in cubic helimagnets: a new intermediate phase at low temperature
• Thermal fluctuations in the conical state of monoaxial helimagnets
• Lock-in of a Chiral Soliton Lattice by Itinerant Electrons
• Monte Carlo study of magnetoresistance in a chiral soliton lattice
• Evolution of Helimagnetic Correlations when approaching the Quantum Critical Point of Mn${}_{1-x}$Fe${}_x$Si
• AC magnetic response of highly nonlinear soliton lattice in a monoaxial chiral helimagnet
• Scattering of spin waves by a Bloch domain wall: effect of the dipolar interaction
• Response of the chiral soliton lattice to spin polarized currents
• Chiral helimagnetic state in a Kondo lattice model with the Dzyaloshinskii-Moriya interaction
• The continuum of metastable conical states of monoaxial chiral helimagnets
• Spin-current diode with a monoaxial chiral magnet