鐵磁/一般金屬異質結構的鐵磁共振與自旋電子學之研究
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2016
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我們使用E-beam lithography和Photo lithography技術將樣品製作成狹長型的結構並且使用Microstrip以及共平面波導(coplanar waveguide,CPW)來輸入微波訊號,目前我們實驗成功的量測到鐵磁共振(ferromagnetic resonanceand,FMR)訊號。
當鐵磁材料/一般金屬異質結構在鐵磁共振的條件下,因為自旋幫補效應(spin pumping effect,SPE),使得自旋流不斷地流入一般金屬。我們利用鐵磁共振的訊號分析磁化飽和量 以及Gilbert阻尼參數 ,比較單層鐵磁材料以及鐵磁/一般金屬異質結構材料的 ,發現鐵磁/一般金屬異質結構的 大於單層鐵磁材料的 ,得知我們使用鐵磁/一般金屬異質結構(Py/Pt)有自旋流成功的產生。
然而自旋電流無法直接地被量測到,但是因為自旋-軌道作用(spin–orbit interaction)導致逆自旋霍爾效應(inverse spin Hall effect,ISHE)進而產生電荷電流,未來我們會在樣品的兩端再加上直流(DC)訊號的量測。在此實驗中除了ISHE還會有自旋整流效應(spin rectification effect,SRE)為了區分這兩種不同訊號的電流,未來我們將會使用了此篇論文[1]的方法來進行室溫實驗的分析,並且使用[2]的方法在低溫環境(< 1.5K)下做測量分析。
We use E-beam lithography and Photo lithography to make slim FM/Normal metal heterostructures.Microwave signal entered by microstrip or coplanar waveguide (CPW)and we success measure ferromagnetic resonanceand (FMR) signal. When FM/Normal metal heterostructures occur ferromagnetic resonanceand,the spin current continuously flow to normal metal because of spin pumping effect (SPE).Then we use FMR signal to analysis saturated magnetization and Gilbert damp parameter . Compare single ferromagnetic layer and FM/Normal metal heterostructures,we find Gilbert damp parameter of heterostructures larger than of single ferromagnetic layer.This result make we know that spin current was produced in FM/Normal metal heterostructures. However , spin current can’t measure directly. But we can measure charge current that resulting in inverse spin Hall effect (ISHE) caused by spin–orbit interaction (SOC). In the future, Our experiment will add DC pad in order to detecting DC signal. Then we will measure ISHE and spin rectification effect (SRE) signal. In order to distinguishing ISEH and SRE signal, we will use this method [1] in room temperature and this method [2] in low temperature (< 1.5K).
We use E-beam lithography and Photo lithography to make slim FM/Normal metal heterostructures.Microwave signal entered by microstrip or coplanar waveguide (CPW)and we success measure ferromagnetic resonanceand (FMR) signal. When FM/Normal metal heterostructures occur ferromagnetic resonanceand,the spin current continuously flow to normal metal because of spin pumping effect (SPE).Then we use FMR signal to analysis saturated magnetization and Gilbert damp parameter . Compare single ferromagnetic layer and FM/Normal metal heterostructures,we find Gilbert damp parameter of heterostructures larger than of single ferromagnetic layer.This result make we know that spin current was produced in FM/Normal metal heterostructures. However , spin current can’t measure directly. But we can measure charge current that resulting in inverse spin Hall effect (ISHE) caused by spin–orbit interaction (SOC). In the future, Our experiment will add DC pad in order to detecting DC signal. Then we will measure ISHE and spin rectification effect (SRE) signal. In order to distinguishing ISEH and SRE signal, we will use this method [1] in room temperature and this method [2] in low temperature (< 1.5K).
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自旋電子學, 鐵磁共振, 自旋幫補效應, 自旋霍爾效應, Spintronics, Ferromagnetic Resonance, Spin Hall Effect, Spin Pumping Effect