Empirically, the rather low-nickel alloy (it's 70-75% copper, as I recall, you can look it up, I'm not bothering right now) that US nickels (currency, coin) are made from ignores a nice strong hard-drive magnet...
It may depend on crystal structure, as does steel (most back-yard heat treaters are aware of steel going non-magnetic as a good temperature indicator of when it might be hot enough to quench, at least if it's plain carbon steel.)
With a small magnet and a Canadian dime? That's how I do it.
The copper-nickel alloy of US 'nickels' is not ferromagnetic.
Presumably you mean at room temperature, 293 K - 298 K? Gadolinium comes close, with a Curie temperature of 292 K, which is about 66°F or 18.8°C. [It's a "silvery-white, malleable and ductile rare-earth metal", per .]
[snip 3 dozen lines]See for a list of Curie temperatures for 16 crystalline ferromagnetic and ferrimagnetic materials. It seems that 6 elements (Fe, Co, Ni, Gd, Dy, Li) have been observed to produce ferromagnetic magnetic fields. Li isn't shown in the chart but is mentioned in a later paragraph, with a Curie temp well below 1 K for Li gas.
Re the original question, although US nickel coins are 1/4 nickel,
3/4 copper*, they seem to be non-ferromagnetic, as mentioned before. *.
I would not think it would be 'FERRO'magnetic even if it was pure nickel. LOL.
Ah, yeah, it is. Cobalt is, too. Ferromagnetism refers today to the physics of one particular magnetism mechanism, not to the material, although obviously that's where the term came from.
Canadian Nickels were or are made from Nickel. I used to use them in experiments that with heat the magnetism would halt with heat and return as it cooled. We could do a swing of sorts.
Buy some nickel wire or a nickel sample sheet. But then save a buck and look at Wiki
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Material Curie temp. (K) Co 1388
That is the term that is used.
The Canadian Nickel (I have a few still) are or were 8 or 12 sided Nickel metal pressings. IIRC, mine have a Beaver on the back - Queen on the front.
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Given the proximity of the rusting carbon steel, wouldn't that provide some measure of cathodic protection?
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