Magnetron sputtering of Superconducting Multilayer Nb3Sn Thin Film

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2.2.3 Analysis and results2.2.3.1 Thickness measurementWe use the sample 4 of each run to measurement the thickness of thin film. Eachof the sample is deposited the thin film on about half of the surface area. Wemeasurement the thickness of each sample five times and average the result.Fig. 2.24 the profile measurement machineFig. 2.25 The measurement traceTable 2.2 The thickness measurement resultsrun Time(min) Current(A) Gas pressure (mbar) Thickness(nm) Deposition rate (nm/s)1 25 0.8 5*10 -3 1660 1.42 20 1.0 5*10 -3 2100 1.73 15 1.2 5*10 -3 1750 1.94 15 1.4 5*10 -3 2080 2.35 20 1.0 3*10 -3 1920 1.66 20 1.2 3*10 -3 2480 2.17 20 1.4 3*10 -3 2610 2.230
Fig. 2.26 The interface of the surface profile measurementAccording to the results, the deposition rate is proportion to the sputteringcurrent and the proceeding gas pressure, which means that the deposition timedetermines the thickness of the thin film and the sputtering current determines thedeposition rate,2.2.3.2 Tc measurementIn order to measurement the critical temperature (T c ), we should use the liquidHelium, because only the liquation point of He (4.2K) is lower than the T c of Nb.We use the four point resistance measurement method to measure the T [30] c . Thefour contacting point are arranged as the last one in Fig. 2.29 by a spring as shown inFig.2.30. The input current is fixed at 10 uA and changed its direction in period of 1second. In the T c measurement instrument, the sample is place on a piece of paperpainted with grease for the good thermal conductor, and the sample should beprevented to contact with copper directly.Because the measurement error and the phase change process, the temperature ofchanging from the normal conductor to superconductor is not a point value. In orderto minimizing the error, we calculate the T c and dT c as follow:TC90%+ TC10%TC= (2.1)2TC90%− TC10%dTC= (2.2)231
Page 1: UNIVERSITÀ DEGLISTUDI DI PADOVAFac
Page 7 and 8: IndexINDEX ........................
Page 9 and 10: IntroductionThe superconductor acce
Page 11 and 12: Fig. 1.1 Disc-loaded traveling-wave
Page 13 and 14: In Type-II superconductors, vortex
Page 15 and 16: needed for preventing the supercond
Page 17 and 18: The B1 crystal structure has a cubi
Page 19 and 20: NbN cavities literature, is often h
Page 21 and 22: superconducting magnet construction
Page 23 and 24: 775°C. From the same diagram, it i
Page 25 and 26: two types of electrons at the Fermi
Page 27 and 28: Of course, there are some other kin
Page 29 and 30: as shown in Fig.2.3. The four opera
Page 31 and 32: Fig.2.8 turbomolecular pumpFig. 2.9
Page 33 and 34: Fig. 2.14 The chamber covered with
Page 35 and 36: Fig. 2.17 the gasket and the magnet
Page 37: shown in Fig. 2.21 and Fig. 2.22. T
Page 41 and 42: Fig. 2.30 put the sample into the T
Page 43 and 44: Fig. 2.34 the performance of the th
Page 45 and 46: 1008038.5°{110}69.6°{211}sample1s
Page 47 and 48: 2dsinθ= nλ (2.3)Fig.2.44 the diff
Page 49 and 50: Chapter 3 Multilayer deposition of
Page 51 and 52: 1 minute. The time of depositing mu
Page 53 and 54: chamber 1 and is connected to the s
Page 55 and 56: 3.2.2.2 Analysis resultⅠ The thic
Page 57 and 58: In order to detect the component of
Page 59 and 60: measure the RRR. So the resistance
Page 61 and 62: 110100903480relative Intensity70605
Page 63 and 64: frequency of the cavity which is in
Page 65 and 66: Fig. 3.28 the inductor coilDuring t
Page 67 and 68: Fig. 3.32 fixing the sample with Nb
Page 69 and 70: second transition temperature is th
Page 71 and 72: source is the bulk Nb sample. Altho
Page 73 and 74: of 1A in the Fig. 3.37 and Fig. 3.4
Page 75 and 76: Table 3.10 the description of the p
Page 77 and 78: 1101001.0A10'-IND3 45 6 7 9 1011 12
Page 79 and 80: 1101009080341.8A10'INDrelative inte
Page 81 and 82: Reference1. A. Godeke, Nb3Sn FOR RA

Magnetron sputtering of Superconducting Multilayer Nb3Sn Thin Film

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