我們在實驗中實現以高頻磁場激發之自旋波發射源，此發射源不需外加直流磁場即可給出4GHz~13GHz頻率之自旋波。
使用自旋波為訊息載體的元件只有自旋角動量傳遞而沒有電荷流動，可以從根本上解決歐姆熱耗散問題，但在近期研究中自旋波的產生往往只能在FMR下伴隨產生，或因為波源的形狀而限制了自旋波頻率，然而在我們的實驗裡以共面波導產生垂直樣品面的高頻磁場，震盪鎳鐵合金(Permalloy﹐Ni81Fe19)線上之圓盤型結構。因強交換耦合作用與形狀異向性，圓盤型結構的鎳鐵合金會形成磁渦漩態(magnetic vortex)，且渦漩態中心會形成一塊垂直方向磁區，而此一磁區可以看作為點波源，此點波源即可解決頻率限制問題，且在這結構下不需直流外加場即可穩定存在，在高頻磁場震盪下即會傳播出自旋波。
由布里淵散射儀(Brillouin light scattering, BLS)量測中，我們觀察到此自旋波由圓盤向外發射，且可以由改變導入共面波導微波的頻率來調控自旋波的頻率，電性量測中證實此自旋波在特定磁場下magnetic vortex會有不同的本徵模式(eigen mode)震盪。 / The study of spin waves (SW) excitation in magnetic devices is one of the most important topics in modern magnetism due to promising applications as information carrier and for signal processing. However, a major challenge for this issue is the requirement to excite propagating spin waves with tunable GHz frequency in the magnonic circuits. We experimentally realize a spin-wave generator, capable of frequency modulation, in a magnonic waveguide. The emission of spin waves was produced by the reversal or oscillation of nanoscale magnetic vortex cores in a NiFe disk array. The vortex cores in the disk array were excited by an out of plane radio frequency (rf) magnetic field. The dynamic behaviors of the magnetization of NiFe were studied using a micro-focused Brillouin light scattering spectroscopy (BLS) setup and electrical measurement. In addition to the discrete ferromagnetic resonance (FMR) signals above external dc saturation magnetic field, we observed clear signals at zero magnetic field where vortex cores are present.
| Identifer | oai:union.ndltd.org:CHENGCHI/G0104755004 |
| Creators | 蔡禮在, Tsai, Li-Zai |
| Publisher | 國立政治大學 |
| Source Sets | National Chengchi University Libraries |
| Language | 中文 |
| Detected Language | English |
| Type | text |
| Rights | Copyright © nccu library on behalf of the copyright holders |
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