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Low temperature conductivity (2.17)

This experiment gives you an idea of how to make conductivity measurement in low temperature regime using a closed cycle helium cryostat, compressor, vacuum unit, chiller/re-circulator and temperture controler. The cryostat can achieve temperatures in the vicinity of 7K when subject to a vacuum of 1 mtorr. Materials like conductors, semiconductors and superconductors are subjected to such measurements.
Sample Results

Resistivity versus temperature plot for Aluminum
Resistivity versus temperature plot for Copper

Labview code

Delta measurement

Matlab Code Van der Pauw
Further Readings and References "A method of measuring specific resistivity and Hall effect of discs of arbitrary shape", L. J. van der Pauw, Philips Res. Repts 13, pp. 1-9, 1958.

Introduction to laboratory cryogenics (Janis Research)
User manual for cryodyne refrigerator (CTI-Cryogenics)

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