Tensile deformations of the magnetic chiral soliton lattice probed by Lorentz transmission electron microscopy

Abstract

We consider the case of a chiral soliton lattice subjected to uniaxial elastic strain applied perpendicular to the chiral axis and derive through analytical modelling the phase diagram of magnetic states supported in the presence of an external magnetic field. The strain induced anisotropies give rise to three distinct non-trivial spin textures, depending on the nature of the strain, and we show how these states may be identified by their signatures in Lorentz transmission electron microscopy (TEM). Experimental TEM measurements of the Fresnel contrast in a strained sample of the prototypical monoaxial chrial helimagnet CrNb 3 S 6 are reported and compare well with the modelled contrast. Our results demonstrate an additional degree of freedom that may be used to tailor the magnetic properties of helimagnets for fundamental research and applications in the areas of spintronics and the emerging field of strain manipulated spintronics.

Chirality-Induced Phonon Dispersion in a Noncentrosymmetric Micropolar Crystal

“…The acoustical activity is also related with first-order spatial dispersion contributions to the elastic constants [5]. This situation is somewhat similar to the role of Dzyaloshinskii-Moriya interaction which leads to a linear Lifshitz invariant in free energy of a chiral helimagnet [7,8]. However, chirality effects are beyond the conventional elasticity theory [9], which considers only a local translation of points and the force stress (force per unit area) but completely ignores a local rotation of these points and the concomitant couple stress (a torque per unit area).…”

Chirality-induced Phonon Dispersion in a Noncentrosymmetric Micropolar Crystal

“…The optical activity is also known to result from a nonlocal response of a crystal to a light wave, when there are first-order spatial dispersion contributions to the dielectric constant determined via the optical gyrotropic tensor. This situation is somewhat similar to a role of Dzyaloshinskii-Moriya interaction which leads to a linear Lifshitz invariant in free energy of a chiral helimagnet [7,8].…”

Magnonic Goos–Hänchen Effect Induced by 1D Solitons

“…If there were an additional anisotropy along an axis perpendicular to the DMI axis, as it happens if the material is under some mechanical stress, the soliton would obey the double Sine-Gordon equation. [15] Let us consider the propagation of spin waves in the presence of one soliton on an otherwise ferromagnetic state. Taking e e z z n n = × and 2 e e z z = , so that ξ 1 and ξ 2 describe the in-plane and out-of-plane oscillations, respectively, K 12 vanishes and Ω 1 and Ω 2 are given by…”

“…Domain walls and their magnonics, with and without DMI, are being extensively studied. [4][5][6][7][8][9][10][11][12] Comparatively, monoaxial helimagnets, in which the DMI acts only along one axis (the DMI axis), have received much less attention, although many experimental and theoretical results concerning their equilibrium [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] and dynamical [32][33][34][35][36][37][38][39][40][41][42][43][44] properties have been obtained.…”