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Magnonic band structure investigation of one-dimensional bi-component magnonic crystal waveguides.

Ma FS, Lim HS, Zhang VL, Ng SC, Kuok MH - Nanoscale Res Lett (2012)

Bottom Line: Our results show that the widths and center frequencies of the bandgaps are controllable by the component materials, the stripe widths, and the orientation of the applied magnetic field.One salient feature of the bandgap frequency plot against stripe width is that there are n-1 zero-width gaps for the nth bandgap for both transversely and longitudinally magnetized waveguides.Additionally, the largest bandgap widths are primarily dependent on the exchange constant contrast between the component materials of the nanostructured waveguides.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, National University of Singapore, Singapore, 117542, Singapore. phylimhs@nus.edu.sg.

ABSTRACT
The magnonic band structures for exchange spin waves propagating in one-dimensional magnonic crystal waveguides of different material combinations are investigated using micromagnetic simulations. The waveguides are periodic arrays of alternating nanostripes of different ferromagnetic materials. Our results show that the widths and center frequencies of the bandgaps are controllable by the component materials, the stripe widths, and the orientation of the applied magnetic field. One salient feature of the bandgap frequency plot against stripe width is that there are n-1 zero-width gaps for the nth bandgap for both transversely and longitudinally magnetized waveguides. Additionally, the largest bandgap widths are primarily dependent on the exchange constant contrast between the component materials of the nanostructured waveguides.

No MeSH data available.


Schematic of the magnonic crystal waveguide comprising of alternating nanostripes of two ferromagnetic materials. The lattice constant a = M + N, where M and N are the respective widths of the stripes of the two materials. A magnetic field H is applied (a) transversely and (b) longitudinally to the waveguide, and q is the wave vector of the SWs.
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Figure 1: Schematic of the magnonic crystal waveguide comprising of alternating nanostripes of two ferromagnetic materials. The lattice constant a = M + N, where M and N are the respective widths of the stripes of the two materials. A magnetic field H is applied (a) transversely and (b) longitudinally to the waveguide, and q is the wave vector of the SWs.

Mentions: We consider a MCW with a length 1,000 nm (x direction) in the form of laterally patterned periodic arrays of alternating stripes of different ferromagnetic materials (Figure 1). Each stripe in the MCW has a length of 140 nm (y direction) and a thickness of 10 nm (z direction). We investigated the magnetization dynamics of bi-component MCWs each composed of two of the following ferromagnetic metals, namely Co, Fe, Permalloy (Py), and Ni, in a total of six possible combinations. For brevity, the MCWs with respective stripe widths of M and N nm of different ferromagnetic materials are referred to as MCo/NNi, MCo/NPy, MCo/NFe, MFe/NNi, MFe/NPy, and MPy/NNi. Two kinds of SW modes, which depend on the orientation of the applied magnetic field H, in transversely and longitudinally magnetized waveguides were investigated as shown in Figure 1a,b, respectively. The magnonic band structures of exchange SWs with wavelengths down to several nanometers and frequencies up to hundreds of gigahertz are numerically investigated.


Magnonic band structure investigation of one-dimensional bi-component magnonic crystal waveguides.

Ma FS, Lim HS, Zhang VL, Ng SC, Kuok MH - Nanoscale Res Lett (2012)

Schematic of the magnonic crystal waveguide comprising of alternating nanostripes of two ferromagnetic materials. The lattice constant a = M + N, where M and N are the respective widths of the stripes of the two materials. A magnetic field H is applied (a) transversely and (b) longitudinally to the waveguide, and q is the wave vector of the SWs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475054&req=5

Figure 1: Schematic of the magnonic crystal waveguide comprising of alternating nanostripes of two ferromagnetic materials. The lattice constant a = M + N, where M and N are the respective widths of the stripes of the two materials. A magnetic field H is applied (a) transversely and (b) longitudinally to the waveguide, and q is the wave vector of the SWs.
Mentions: We consider a MCW with a length 1,000 nm (x direction) in the form of laterally patterned periodic arrays of alternating stripes of different ferromagnetic materials (Figure 1). Each stripe in the MCW has a length of 140 nm (y direction) and a thickness of 10 nm (z direction). We investigated the magnetization dynamics of bi-component MCWs each composed of two of the following ferromagnetic metals, namely Co, Fe, Permalloy (Py), and Ni, in a total of six possible combinations. For brevity, the MCWs with respective stripe widths of M and N nm of different ferromagnetic materials are referred to as MCo/NNi, MCo/NPy, MCo/NFe, MFe/NNi, MFe/NPy, and MPy/NNi. Two kinds of SW modes, which depend on the orientation of the applied magnetic field H, in transversely and longitudinally magnetized waveguides were investigated as shown in Figure 1a,b, respectively. The magnonic band structures of exchange SWs with wavelengths down to several nanometers and frequencies up to hundreds of gigahertz are numerically investigated.

Bottom Line: Our results show that the widths and center frequencies of the bandgaps are controllable by the component materials, the stripe widths, and the orientation of the applied magnetic field.One salient feature of the bandgap frequency plot against stripe width is that there are n-1 zero-width gaps for the nth bandgap for both transversely and longitudinally magnetized waveguides.Additionally, the largest bandgap widths are primarily dependent on the exchange constant contrast between the component materials of the nanostructured waveguides.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, National University of Singapore, Singapore, 117542, Singapore. phylimhs@nus.edu.sg.

ABSTRACT
The magnonic band structures for exchange spin waves propagating in one-dimensional magnonic crystal waveguides of different material combinations are investigated using micromagnetic simulations. The waveguides are periodic arrays of alternating nanostripes of different ferromagnetic materials. Our results show that the widths and center frequencies of the bandgaps are controllable by the component materials, the stripe widths, and the orientation of the applied magnetic field. One salient feature of the bandgap frequency plot against stripe width is that there are n-1 zero-width gaps for the nth bandgap for both transversely and longitudinally magnetized waveguides. Additionally, the largest bandgap widths are primarily dependent on the exchange constant contrast between the component materials of the nanostructured waveguides.

No MeSH data available.