Magnetic skyrmion annihilation by quantum mechanical tunneling
Abstract
Magnetic skyrmions are nano-scale magnetic states that could be used in various spintronics devices. A central issue is the mechanism and rate of various possible annihilation processes and the lifetime of metastable skyrmions. While most studies have focused on classical over-the-barrier mechanism for annihilation, it is also possible that quantum mechanical tunneling through the energy barrier takes place. Calculations of the lifetime of magnetic skyrmions in a two-dimensional lattice are presented and the rate of tunneling compared with the classical annihilation rate. A remarkably strong variation in the onset temperature for tunneling and the lifetime of the skyrmion is found as a function of the values of parameters in the extended Heisenberg Hamiltonian, i.e. the out-of-plane anisotropy, Dzyaloshinskii-Moriya interaction and applied magnetic field. Materials parameters and conditions are identified where the onset of tunneling could be observed on a laboratory time scale. In particular, it is predicted that skyrmion tunneling could be observed in the PdFe/Ir(111) system when an external magnetic field on the order of 6T is applied.
- Publication:
-
New Journal of Physics
- Pub Date:
- August 2020
- DOI:
- 10.1088/1367-2630/ab9f6d
- arXiv:
- arXiv:1906.00196
- Bibcode:
- 2020NJPh...22h3013V
- Keywords:
-
- skyrmion;
- tunneling;
- lifetime;
- instanton;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- doi:10.1088/1367-2630/ab9f6d