零維奈米鉛粉粒超導磁穿透深度與粒徑關係探討; Penetration depth of superconductor in Pb nano particles

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/7311

Title:	零維奈米鉛粉粒超導磁穿透深度與粒徑關係探討;Penetration depth of superconductor in Pb nano particles
Authors:	賴佳伶;Chai-Ling Lai
Contributors:	物理研究所
Keywords:	穿透深度;Penetration depth
Date:	2003-06-20
Issue Date:	2009-09-22 10:54:57 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	我們以熱蒸鍍法備製鉛奈米顆粒，利用X光繞射判定粒徑分別為4.5nm、6nm、7.5nm、9nm、13nm的鉛奈米顆粒。由交流磁化率實驗發現，鉛奈米顆粒的臨界磁場以增大至90KOe以上。利用倫敦穿透深度來擬合交流磁化率實驗，發現在4.5nm鉛奈米顆粒已有量子效應的出現，擬合的結果可知當鉛奈米顆粒粒徑分別為6nm、7.5nm、9nm、13nm時，穿透深度分別為 3.779 nm、 0.658 nm、2.734 nm、30.699 nm ，可知鉛奈米顆粒的穿透深度隨著粒徑變小而變小。由於在奈米顆粒的零維系統下，磁通量並沒有完全穿透奈米顆粒，奈米顆粒由於外加磁場Ha所增加的內能比起塊材因外加磁場Ha比較所增加的內能小很多。擬合出的γ值，隨著粒徑變小而變小，耦合的強度會變大。與先前發現粒徑變小時，表面聲子的密度變大，電子與電子之間的交互作用力會變大相符合。 We made our Pb nanoparticles by thermal evaporation.Determine the sample diameter by X-Ray scattering.we observe the penetration depth is getting flat when the sample diameter is smeller.Because magnetic flux is expected to penetrate appreciably into particles,so that the increase in the internal energy due to the presence of applied magnetic field is much smaller for nanoparticles,when compared to that for bulk and mesoscopic system.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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