摘要(英) |
Abstract
We measure the superconductivity and magnetic properties of In/Ag nanocomposites by tuning interparticle separations. The indium and silver nanoparticles were fabricated by thermal evaporation method. The mean diameters, determined from the peak width of the X-ray diffraction patterns, are 9 nm and 9.6 nm for In and Ag, respectively.
The superconductivity and magnetic properties were measured on PPMS (Physical Property Measurement System). The variation magnetization M with the applied magnetic field can be described by Langevin function plus a Lenz’s diamagnetic term χd.The diamagnetic χd with high packing fraction f is weaker than low packing fraction f.
The χ’(T) curves can fit to the Scalapino’s equation, giving the superconducting parameters such as Tc, χsc and λ0. The Tc doesn’t change significantly upon increasing the packing fraction f. Howerver, the superconductor diamagnetic screening signals largely increase in the high packing fraction sample. We suggest that there is a new superconductor diamagnetic component emeraging at low temperature in the high packing fraction sample. We propose that the new superconductor component is induced in Ag nanoparticles by In nanoparticles. |
參考文獻 |
參考文獻
[1] B. Mühlschlegel, D. J. Scalapino, and R. Denton, Phys. Rev. B 6, 1767 (1972).
[2] 張裕恒,李玉芝,超導物理,儒林圖書公司(1997)
[3] F.-Y. Wu, C. C. Yang, C.-M. Wu, C.-W. Wang, and W.-H. Li,
J. Appl. Phys. 101, 09G111 (2007)
[4] Th. Bergmann, K. H. Kuhl, B. Schröder, M. Jutzler, F. Pobell, Journal of Low Temperature Physics, Volume 66, Issue 3-4, p 209-237(1987)
[5] 陳皇男, 顆粒間交互作用對銦奈米顆粒熱臨界擾動效應的影響(2011)
[6] 黃竑杰,零維銦奈米微粒的超導參數探討(2011)
[7] Sangita Bose and Pushan Ayyub, PHYSICAL REVIEW B 76, 144510 (2007)
[8] 吳泰柏, 許樹恩, X光繞射原理與材料結構分析
[9] 王進威, 擬合X光繞射峰形判定奈米微粒粉末的粒徑分佈(2006)
[10] Nicola A.Spaldin,MAGNETIC MATERIALS
[11] V. L. Ginzburg and L. D. Landau, Zh. Eksperim. Iteor. Fiz. 20, 1064(1950)
[12] W.Meissner and R.Ochsenfeld,Naturwiss,21(1993),787
[13] Neil W.Ashcroft and N.David Mermin,Solid State Physics
[14] C. Kittel, Introduction to Solid State Physics, 7th. edition (Willy, NewYork, 1996)
[15] Superconductivity of metals and alloys, P.G. de Gennes, translated by P.A. Pincus. |