Ultrasonic elastic responses in monopole lattice
arXiv:1608.06362 · doi:10.1088/1367-2630/aa6322
Abstract
The latest experimental advances have extended the scenario of coupling mechanical degrees of freedom in chiral magnets (MnSi/MnGe) to the topologically nontrivial skyrmion crystal and even monopole lattices. Equipped with a spin-wave theory highlighting the topological features, we devise an interacting model for acoustic phonons and magnons to explain the experimental findings in a monopole lattice with a topological phase transition, i.e., annihilation of monopole-antimonopole pairs. We reproduce the anisotropic magnetoelastic modulations of elastic moduli: drastic ultrasonic softening around the phase transition and a multi-peak-and-trench fine structure for sound waves parallel and orthogonal to the magnetic field, respectively. Comparison with experiments indicates that the magnetoelastic coupling induced by Dzyaloshinskii-Moriya interaction is comparable to that induced by the exchange interaction. Other possibilities such as elastic hardening are also predicted. The study implies that the monopole defects and their motion in MnGe play a crucial role.
New J. Phys. (2017)
References in corpus (10)
- Spontaneous Skyrmion Ground States in Magnetic Metals
- Magnetic skyrmion logic gates: conversion, duplication and merging of skyrmions
- Rotating skyrmion lattices by spin torques and field or temperature gradients
- Memory functions of magnetic skyrmions
- Formation of a topological non-Fermi liquid in MnSi
- Theory of helical spin crystals: phases, textures and properties
- Pinning and movement of individual nanoscale magnetic skyrmions via defects
- Phenomenology of current-induced skyrmion motion in antiferromagnets
- Electric transport in three-dimensional Skyrmion/monopole crystal
- Inexhaustible physics of the helical magnet MnSi: field evolution of the magnetic phase transition inferred from ultrasound studies
Cited by in corpus (7)
- Phonon Magnetochiral Effect
- Homogeneous and heterogeneous nucleation of skyrmions in thin layers of cubic helimagnets
- Theory of magnetoelastic resonance in a mono-axial chiral helimagnet
- Tensile deformations of the magnetic chiral soliton lattice probed by Lorentz transmission electron microscopy
- Phase degree of freedom and topology in multiple- spin textures
- Nonlinear emergent elasticity and structural transitions of skyrmion crystal under uniaxial distortion
- Theory of collective excitations in the quadruple- magnetic hedgehog lattices