Dynamics of Composite Domain Walls in Multiferroics in Magnetic Field and Their Instability
| Autor: | Koji Kawahara, Hirokazu Tsunetsugu |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Physics
Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Spins Composite number Dynamics (mechanics) FOS: Physical sciences General Physics and Astronomy Instability Magnetic field Domain (software engineering) Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Antiferromagnetism Condensed Matter::Strongly Correlated Electrons Multiferroics |
| Zdroj: | Journal of the Physical Society of Japan. 90:014703 |
| ISSN: | 1347-4073 0031-9015 |
| DOI: | 10.7566/jpsj.90.014703 |
| Popis: | We study theoretically the dynamics of composite domain walls (DW) in multiferroic material GdFeO${}_3$ driven by magnetic field $H$. Two antiferromagnetic orders of Fe and Gd spins interact Gd-ion displacement in this system with coupling $c$ at low temperatures, and we have numerically simulated the corresponding time-dependent Ginzburg-Landau equations in which magnetic field $H$ couples to Fe-spin order parameter. We vary $H$ and $c$ systematically and calculate velocity $v$ and inner structure in a stationary state for magnetic DW and magneto-electric DW. DW mobility $v/H$ increases with $H$ and decreases with $c$ for both DWs, but their characteristics differ between the two. We have also studied analytically the smooth characteristics of magneto-electric DW by perturbation theory. Another finding is a splitting instability at large H. A magneto-electric DW splits into a pair of magnetic DW and electric DW when $c$ is large, while a magnetic DW splits when $c$ is small. Internal structure of composite DW deforms with increasing $c$ and $H$, and modulations in different order parameters separate in space. Their relative distances show a noticeable enhancement with approaching the splitting instability. Comment: 11 pages, 10 figures, submitted to Journal of the Physical Society of Japan |
| Databáze: | OpenAIRE |
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