鎳含量對於銦-鎳奈米複合材料電傳輸與磁阻現象之影響; The influence on electric transportation and magnetic resistance properties in In-Ni nanocopact with different nickel compostition.

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題名:	鎳含量對於銦-鎳奈米複合材料電傳輸與磁阻現象之影響;The influence on electric transportation and magnetic resistance properties in In-Ni nanocopact with different nickel compostition.
作者:	簡紹文;Shao-Wun Jian
貢獻者:	物理研究所
關鍵詞:	電傳輸與磁阻現象之影響;In-Ni nanocopact with different nickel compostit
日期:	2007-06-20
上傳時間:	2009-09-22 10:59:26 (UTC+8)
出版者:	國立中央大學圖書館
摘要:	採用銦與鎳兩種奈米微粒，以各種不同質量比例調配之後均勻混合，施加特定的壓力，製成In/Ni奈米壓合材料，為樣品命名為(In)100-x(Ni)x_CD，其中x=0、50、70、80、85、90及95。由於鎳的導電性比銦差，因此可視為絕緣體，用來增加銦微粒之間的距離，來探討磁性奈米壓合材料的電子傳輸機制。調製樣品內銦與鎳奈米微粒質量比例，鎳微粒在外加磁場下影響電子的傳輸，造成磁阻現象。當樣品中鎳含量在70%以下時，電子主要的傳導路徑為銦微粒所形成的導電通路，因此電性較相似。鎳含量大於80%時，電子的傳導機制變為銦－鎳－銦間傳導，甚至變成鎳與鎳之間傳導為主要通路。在樣品的電性為金屬性時，由於主要的傳導路徑在銦微粒中，而銦為金屬材料，推測其磁阻現象為常磁阻；隨著鎳含量的增加，當樣品的電性為非金屬性時，假如主要的傳導為鎳微粒間相互傳導，所以我們以穿隧磁阻來解釋其磁阻現象。在高外加磁場區發現磁阻有緩慢增加的趨勢，而穿隧磁阻並不能解釋此現象，所以我們猜測其原因可能是微粒中的常磁阻所貢獻，因此在非金屬性樣品的磁阻現象為穿隧磁阻與常磁阻所貢獻的結果。 The nanoparticle compacts were fabricated by evenly mixing indium and nickel nanoparticles with several different mass ratios. The nanoparticle compacts were fabricated on the same pressure. The nanocompacts of 1-x/x mass ratio for In/Ni was called as (In)1-x(Ni)x_CD. Its relative mass density with respect to the bulk material would be used to denote the compacting density (CD). Because the conductivity of nickel is less than indium, we can treat the nickel particles as insulator. We can use nickel particles to increase of the distance between indium particles. We probe into the transport mechanism of the magnetic nanocompact material in different distance of indium particle. In different mass ratios, the nickel particle in magnetic field influences the transportation more, cause magnetic resistance. If the nickel composition in the sample is less than 70%, the electrons is transported by the route formed on indium particle. Then the electric property is similar. If the nickel composition in sample is more than 85%, the transport mechanism becomes indium-nickel- indium or nickel-nickel transportation. When the electric property of sample is metallic, the major conductive route is in indium particles. Because indium is metal, we suggest that the magnetic resistance is ordinary magnetoresistivity (OMR). When the nickel composition is increasing, the electric property of sample becomes non-metallic. If the major transportation is become nickel-nickel tunneling, we explain the magnetic resistance with tunneling magnetoresistivity (TMR).In high applied magnetic field, the magnetic resistance is slowly increasing as applied magnetic field is increasing . TMR can not make a description of this result, so we guess that the reason could be OMR in particle. Then, the magnetic resistance is contributed by TMR and OMR.
顯示於類別:	[物理研究所] 博碩士論文

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