What is the resistivity of copper at 3 kelvin?

Question

I couldn't find the value of resistivity of copper at 2.73K on google

Strongly related: https://physics.stackexchange.com/q/241274/ — Nilay Ghosh, Aug 12 '19 at 03:48

Farcher · Accepted Answer · 2019-08-13T12:39:11.210

16

There is a problem with answering your question in that at such a low temperature the resistivity of copper is very much determined by the impurities and crystallographic defects eg dislocations, voids etc, which may be present.
At low temperatures it is the scattering of free electrons by impurities and crystallographic defects which determine the resistivity rather than the thermal excitation of the copper ions.

The parameter which is often measured is the residual resistance ratio $\dfrac{R_{\text{273 K}}}{R_{4.2\,\rm K}}$ which for fairly pure copper wire as used for telephone lines might be of the order of $100$.

Large single crystals of very pure copper can be produced with residual resistance ratios in the thousands.

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I have annotated the graph to illustrate the non-linear logarithmic scale and how to find the resistivity of copper at $3\, \rm K$.

edited Aug 13 '19 at 12:39

answered Aug 08 '19 at 19:12

Farcher

95,680

so it's impossible to use copper at any temperature around 3k as a conductor – AJK Aug 08 '19 at 19:16
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@AJK That is not what I wrote. From the graph you can get an estimate of the resistivity of “ordinary” copper at around $3,\rm K$. At this temperature the copper is a much better conductor of electricity than at room temperature. – Farcher Aug 08 '19 at 19:19
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How do we get the estimate – AJK Aug 08 '19 at 19:23
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@AJK From the graph noting that it is a log-log graph. – Farcher Aug 08 '19 at 19:24
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I have no clue what that means – AJK Aug 08 '19 at 19:24
Did you mean that it's has a very low resistivity – AJK Aug 08 '19 at 19:28
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@AJK Yes, it is a much better conductor at low temperatures. – Farcher Aug 08 '19 at 19:35
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Do you know what a logarithmic axis is? Both axes in the graph are logarithmic, which makes it “log-log”. – G. Smith Aug 08 '19 at 20:12
Where did you find this graph? I never saw a log scale with 3/30/300 as its 'major' tics before. Sure it works, but - WHY? – asdfex Aug 09 '19 at 09:17
@asdfex probably because there's no data for <=3 so it would just be a huge waste of space – OrangeDog Aug 09 '19 at 10:20
@asdfex The graph was slide 28 from a set of slides produced by CERN – Farcher Aug 09 '19 at 10:37
All SE posts are version controlled, so please do not make your post look like a revision table, instead just seamlessly integrate the new material into the post. There is an edit history button at the bottom of the post for those interested in seeing what changed. – Kyle Kanos Aug 13 '19 at 11:54
@KyleKanos Thanks for the reply. I will amend my answers as I come across them. – Farcher Aug 13 '19 at 12:27

What is the resistivity of copper at 3 kelvin?

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