Master Thesis Effect of vortex shaking on the ... - Physik-Institut

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Figure 5: Structure <strong>of</strong> YBCO with the CuO 2 planes. In NdBCO the Yttrium atoms are replaced by Neodymium. 7 6 5 H||c K 0.0 96.76 3.0 90.92 5.0 88.11 6.0 86.91 7.0 85.71 7.0 85.65 4 µ 0 H(T) 3 2 1 0 84 86 88 90 92 94 96 98 Temperature in K Figure 6: Location <strong>of</strong> the melting transition in the magnetic phase diagram. (Data from specific-heat measurements.) 10
3 The Experiment 3.1 Design The experimental setup was as follows: As a base plate I used a synthetic sapphire disk, which was chosen because <strong>of</strong> its good thermal conductance and electrical insulation. On top <strong>of</strong> it, on the right, a copper ’gibbet’ was attached with GE-Varnish to the sapphire to support the crystal. On the left side, a copper coil for the ac field was set on an unattached copper plate, making it possible to move it over the crystal and back again. This coil had an inductance <strong>of</strong> about 0.20 mH, with about 200 windings producing a magnetic field <strong>of</strong> ∼ 1.8 - 3 Oe/mA. See sketch 7 and sketch 22 in the appendix for further details <strong>of</strong> the setup. Unfortunately it took an immense amount <strong>of</strong> time to gather and prepare these components due to the variety <strong>of</strong> people and institutions involved and the Christmas holiday break, which delayed the delivery <strong>of</strong> the sapphire platelets for almost a month. Originally a four-wire resistivity measurement was planed, but due to the problems mentioned in 3.3, only two-wire measurements could be made. The system used to measure the resistivity and to drive the coil was the 6 1 2.4 1.5 3 10 00000000000000 11111111111111 00000000000000 11111111111111 00000000000000 11111111111111 00000000000000 11111111111111 00000000000000 11111111111111 6 00000000000000 11111111111111 00000000000000 11111111111111 00000000000000 11111111111111 00000000000000 11111111111111 1 00000000000000 11111111111111 00000000000000000 11111111111111111 1.6 5 0000000000 1111111111 0000000000 1111111111 0000000000 1111111111 0000000000 1111111111 0000000000 1111111111 0000000000 1111111111 0000000000 1111111111 4 0000000000 1111111111 0000000000 1111111111 2.5 0000000000 1111111111 0000000000 1111111111 0000000000 1111111111 0000000000 1111111111 4.5 ApiezonN GeVarnish Figure 7: Sketch <strong>of</strong> the experimental setup, side view. Physical Property Measurement System (PPMS) <strong>of</strong> Quantum Design, see [3] and [5], with the optional AC Transport Option. 11
Page 1 and 2: Master The
Page 3 and 4: 1 Introduction The decision to writ
Page 5 and 6: for lower temperatures and a <stron
Page 7 and 8: 2.1.2 The melting transition Let us
Page 9 and 10: on one single crystal the differenc
Page 11: Figure 4: Scheme of</strong
Page 15 and 16: x 10 −5 2 0 Resistance in Ohm −
Page 17 and 18: Figure 9: Scattered data in the gra
Page 19 and 20: 0.49 0.48 0.47 0.4345 0.434 Resista
Page 21 and 22: some problems in finding an appropr
Page 23 and 24: 2.53 x 10−4 0 to 7T 2.52 Resistan
Page 25 and 26: Figure 16: To approach of</
Page 27 and 28: Figure 18: Results of</stro
Page 29 and 30: 4 Interpretation and Conclusion 4.1
Page 31 and 32: 5 Appendix Figure 20: In-plane resi
Page 33 and 34: Figure 23: Comparison of</s
Page 35 and 36: List of Figures 1
Page 37 and 38: References [1] J. Bardeen, L. N. Co

Master Thesis Effect of vortex shaking on the ... - Physik-Institut

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