PLD製作Py(100)/Cu(100)/H-Si(100)薄膜與其磁性行為研究

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2014

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利用脈衝雷射沉積(Pulsed laser deposition, PLD)法在室溫下製作厚度5nm至100nm之銅與鎳鐵 (Ni80% Fe20%, Py)薄膜於H-Si(100)基板上,Cu(100)為了降低晶格失配度從33.3 %降為5.7 %,故旋轉45度使Cu[100]平形H-Si[110]進行磊晶,樣品經X光繞射實驗確定單晶Cu(100)結構生成。FCC-Py(100)因與FCC-Cu(100)間的晶格失配度為1.7%,因此Py(100)可穩定地磊晶於Cu(100)上。藉由X光ϕ-scan的量測也證實基板與薄膜間的晶向關係為Si [110]//Cu[010]//Py[010]。而[Py/Cu]10的多層膜樣品在X光繞射實驗上發現具有超晶格結構。 在磁性量測上,由LMOKE發現樣品具有單軸磁異向性,並且易磁化軸與難磁化軸分別平行於Py[010]與Py[100],單軸磁異向性可能是由於晶格失配度產生應變,破壞FCC-Py的四重對稱所造成。從這次的研究結果發現,樣品的矯頑場隨著Py厚度的增加從1.7Oe增加到3.0Oe。其他的磁性參數由FMR量測結果經計算得出,阻尼常數當Py厚度為10nm時,有最小值 1.25×〖10〗^(-2),之後分別因為渦電流效應與晶格失配度導致阻尼常數隨著Py薄膜厚度的增加或減少皆為上升。
Epitaxial Permalloy (Ni80% Fe20%, Py) and Cu film with the different thickness from 5 nm to 100 nm were prepared on H-Si (100) substrate by the method of PLD at room temperature. In order to reduce lattice mismatch from 33.3 % to 5.7 %, the Cu [100] is parallel to the H-Si[110]; that is, the Cu(100) lattice mesh is rotated 45 with respect to H-Si[100] . Hence surface construction of Cu(100)R45-H-Si(100) is formed. As revealed by XRD ϕ-scan measurement, Py lattice sits on top of Cu(100),with Si[110]//Cu[010]// Py[010]. XRD information also revealed the good quality of epitaxy of Py/Cu resulting on the Si(100)(1x1)-H . The in-plane uniaxial behavior of the Py (100), with the easy axis and hard axis each is parallel to Py [010] and Py [001], is measured by LMOKE. This is due to the 1.7 % lattice mismatch which induces the stress anisotropy to break the 4-fold symmetry. In this studies, the coercivity of the samples is from 1.7 Oe to 3.0 Oe with the increase of the Py thickness. In addition, the other magnetic parameters are determined by the FMR measurement. The minimum damping constant is 1.25×〖10〗^(-2), when the Py thickness is 10 nm. As the Py thickness reduce and increase, the damping constant will increase due to lattice misfit and the eddy current effect, respectively.

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磁性, 鎳鐵, 脈衝雷射沉積, 鐵磁共振, 柯爾磁光, magnetism, Permalloy, Pulsed laser deposition, FMR, MOKE

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