arXiv subjects

K. Di

Publications and source records attributed to K. Di.

2 recordsLinked to original sources

arXiv2014

Tuning the Band Structures of a 1D Width-Modulated Magnonic Crystal by a Transverse Magnetic Field

Theoretical studies, based on three independent techniques, of the band structure of a one-dimensional width-modulated magnonic crystal under a transverse magnetic field are reported. The band diagram is found to display distinct behaviors when the transverse field is either larger or smaller than a critical value. The widths and center positions of bandgaps exhibit unusual non-monotonic and large field-tunability through tilting the direction of magnetization. Some bandgaps can be dynamically switched on and off by simply tuning the strength of such a static field. Finally, the impact of the lowered symmetry of the magnetic ground state on the spin-wave excitation efficiency of an oscillating magnetic field is discussed. Our finding reveals that the magnetization direction plays an important role in tailoring magnonic band structures and hence in the design of dynamic spin-wave switches.

cond-mat.mtrl-sci↗

arXiv2013

Comment on "Physical Origin and Generic Control of Magnonic Band Gaps of Dipole-Exchange Spin Waves in Width-Modulated Nanostrip Waveguides" [K.-S. Lee, D.-S. Han, and S.-K. Kim, PRL 102, 127202 (2009), arXiv:0811.0411]

In Ref. [PRL 102, 127202 (2009)] Lee et al. reported the existence of large magnonic bandgaps in one-dimensional width-modulated Permalloy nanostripe waveguides based on OOMMF simulations. However, as the symmetry of the magnetic field pulse they applied to excite the spin waves (SWs) was not general, the entire set of SW branches with A symmetry was omitted from the magnonic band structures (see below). This omission has unfortunately led to misleading conclusions of, for instance, the number, width and position of the bandgaps. We present here the full band structure based on three different theoretical approaches that gave consistent predictions, thus corroborating the methods employed, namely, a microscopic approach, OOMMF simulations, and a method based on the linearized Landau-Lifshitz equation. Further, we provide a physical interpretation using group theory.

cond-mat.mes-hall↗