4 ms·
A 4-point measurement of an insulator would show zero current, as far as I know. A more plausible idea IMO is that it could be a 4-point measurement of a highl
by amluto 3y ago
A 4-point measurement of an insulator would show zero current, as far as I know.
A more plausible idea IMO is that it could be a 4-point measurement of a highly inhomogeneous sample. If the current probes make contact with conductive parts of the sample, and there is a conductive path between them, but one or both voltage probes are not contacting the conductive path, then the voltage measurement would be garbage and potentially zero.
I don’t think this is much of a problem when measuring conventional conductors (you don’t need a particularly good contact, which is much of the point), but a lot of superconductors are oddball materials where, under conditions where they fail to superconduct, they barely conduct at all.
So maybe the sample has a conducting phase and an insulating phase?
- BizarroLand 3y agoWouldn't it be odd for an amalgam of lead and copper to be non-conductive? I know they were formed from sulfur compounds, but the production process should have eliminated those compounds, and the final forming is done in a vacuum so there shouldn't be any oxide generation to form non-conductive barriers. I don't know much about the process but shouldn't they be testing resistance in a superconductor?
- scentoni 3y agoIt’s not an amalgam (that means a mercury alloy) or any metallic alloy. It’s an oxide (more complicated than that but there’s more oxygen atoms than metal atoms).
- BizarroLand 3y agoAmalgam can also mean, "A mixture or combination of different things" such as "an amalgam of musical genres" or "an amalgam of unsavory dog food flavors", which, since we aren't talking about mercury at all, nor are we talking about any form of dentistry, should have be evident and deducible from the context. https://www.oxfordlearnersdictionaries.com/definition/english/amalgam https://www.oxfordlearnersdictionaries.com/definition/englis... And we very much are talking about an alloy, which is a "metallic substance composed of two or more elements" https://www.britannica.com/technology/alloy https://www.britannica.com/technology/alloy Lead is a metal. Copper is a metal, a combination of 2 metals is an alloy. However, you are right, I did overlook that the compound is an oxide, my bad.
- singularity2001 3y agoA 4-point measurement of an insulator would show zero current, as far as I know. The blog post suggests it might be electrical breakdown of the material at a certain voltage