增強鎳(Ni)參雜錫(Sn)奈米粒子的超導性;Enhanced superconductivity in Ni-doped Sn nanoparticles

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題名:	增強鎳(Ni)參雜錫(Sn)奈米粒子的超導性;Enhanced superconductivity in Ni-doped Sn nanoparticles
作者:	古亦娜;Gultom, Vina Agustina
貢獻者:	物理學系
關鍵詞:	SnO2;納米粒子;X 射線衍射;超導性;SnO2;nanoparticles;x-ray diffraction;superconductivity
日期:	2019-01-25
上傳時間:	2019-04-02 14:33:08 (UTC+8)
出版者:	國立中央大學
摘要:	本研究探討了Sn 和Ni 納米顆粒（NPs）複合體系的超導（SC）現象。我們分析了Sn 摻雜Ni 的合成壓力對四方相形成的影響。通過熱蒸發方法製造Sn 和Ni 納米顆粒，使用兩個分離的蒸發源進行單獨蒸發; 並且藉由各種惰性氣體的壓力的控制顆粒的尺寸。對於Sn 側，加熱電流為~50A，對於Ni 側，加熱電流為~80A，相應的氬氣壓力為0.18 托和0.08 托。使用X 射線繞射法進行晶體結構的表徵分析，然後與Rietveld 精製結合以確定樣品組成和微晶尺寸。對於第1，第2 和第3 樣品的微晶尺寸分別達到 34.6（9）nm，33.8（9）nm 和30.1（2）。在1.8K 和未施加磁場下測量這些樣品的AC 磁化率，從而出現超導狀態。使用 Scalapino 配件測試每個樣品。 Scalapino 擬合是通過關聯磁化率和溫度來確定超導參數的良好描述。此外，當施加磁場Ha = 0 Oe 時，隨著樣品的粒徑減小，電子間隙δ 也變大，穿透深度變大，0.192（8）nm，δ= 0.00206（4）kBTC，0.26 （1）nm 與δ= 0.01 （7）kBTC，1.1（2）nm，δ= 0.08（4）kBTC，表明施加的磁場將完全穿透納米粒子，並導致抗磁效應被完全破壞。當樣品的微晶尺寸變小時，臨界磁場增加，這意味著抗磁效率越來越好。令人驚訝的是，30.1（2）nm 的臨界溫度比塊體的臨界溫度高108 倍（可接受的錫邊界溫度實驗值為3.722K）。此特殊樣品具有SnO2 結構，因此提升了臨界溫度。;Herein, this study reports the superconductivity (SC) phenomena of Sn and Ni nanoparticles (NPs) composite systems. We analyzed the influence of the synthesis pressure of Sn-doped Ni in the formation of the tetragonal phase. Sn and Ni nanoparticles have been fabricated by the thermal evaporation method with two decoupled evaporation sources for separate evaporation; and the size of particles with various inert gas pressures was controlled. The heating current is ~50 A for Sn side and ~80 A for Ni side with the respective argon pressure of 0.18 torr and 0.08 torr. The characterization of crystal structure was performed using experimental techniques such as X-ray diffraction method, then allied with Rietveld refinement to determine the sample composition and crystallite size. The crystallite size of these samples were achieved 34.6(9) nm, 33.8(9) nm and 30.1(2), respectively for the sample 1, sample 2 and sample 3. The AC susceptibility of these samples was measured at 1.8 K and zero applied magnetic field, thus the superconducting state appeared. Each sample was tested using the Scalapino fitting. Scalapino fitting is a good description to determine the superconducting parameters by relating the magnetic susceptibility and temperature. In addition, when applied magnetic field Ha = 0 Oe, the penetration depth becomes larger as the particle size of the sample decreases and the electron gap δ become larger as well, 0.192(8) nm with δ = 0.00206(4) kBTC, 0.26(1) nm with δ = 0.01(7) kBTC, 1.1(2) nm with δ = 0.08(4) kBTC, respectively, indicating that the applied magnetic field will completely penetrate the nanoparticles, and causing the diamagnetic effect to be completely destroyed. Surprisingly, the critical temperature of 30.1(2) nm is achieve higher 108 times than that of the bulk (the accepted experimental value of the tin boundary temperature is 3.722K) kOe. This interesting sample has SnO2 structure and it made an enhancement on the critical temperature.
顯示於類別:	[物理研究所] 博碩士論文

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