I never thought that modern-day American nickels actually contained nickel anymore. However, follow to this wiki article, the coins actually execute contain 25% nickel, the rest being copper. And yet, no us coin created today is official magnetic. Why is this alloy of nickel no attracted come a magnet?

(and yes, i tried time and also again come find and also answer somewhere else online.)


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There are many varieties of magnetic properties, consisting of ferromagnetism, paramagnetism, diamagnetism, antiferromagnetism, ferrimagnetism, superparamagnetism, metamagnetism, turn glasses, and helimagnetism. Numerous of these are too weak to cause any noticeable interaction with a magnet. The kind of daily magnetism you"re reasoning of, which nickel has, is ferromagnetism.

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While nickel is ferromagnetic, copper is not. Together you said, the American nickel is right now 25% nickel and also 75% copper. Follow to this file (from 1931!), in order for a nickel-copper alloy to it is in ferrogmagnetic, it have to contain at the very least 56% nickel:

... 56 percent nickel is required before the alloy reflects ferromagnetic nature at simple temperatures.

https://journals.aps.org/pr/abstract/10.1103/PhysRev.38.828

E. H. Williams, Magnetic properties of Copper-Nickel Alloys. Phys. Rev. 38, 828 (1931).


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edited Apr 4 "20 in ~ 3:51
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None of the us coins are magnetic (ferromagnetic), except for the 1943 Lincoln penny (Steel Cents, do in steel and zinc to conserve copper for ammunition throughout wartime), which are considered magnetic. Almost all of those coins various other than Steel Cents are made with greater percentage the copper ($ceCu$) and lower percentages the other metals such as nickel ($ceNi$), zinc ($ceZn$), etc. (mostly $ceNi$). For example, current 5-Cent us coin (US Nickel) is make of 75% $ceCu$ and also 25% $ceNi$, together OP listed in the question. Friend can uncover some percentages in united state coins in this AZO products Article.

Pure $ceNi$ is magnetic in ~ room temperature when $ceCu$ is not. Yet, why US Nickel is not magnetic?

The magnetic nature of $ceCu/Ni$ alloys have been learned by number of researchers (e.g.

See more: Which Statement About How Mass Media Have Changed Over Time Is Most Accurate?

, Ref.1 and 2), perhaps since their use in alloys goes earlier at least two thousands years, at the time, the knowledge of the ingredient of alloy was unknown (Note: the elemental nickel was just discovered fairly late on). Follow to this research, pure $ceNi$ is magnetic v its Curie temperature being about $pu527 K$ (Curie temperature or Curie point is whereby a steel loses that is ferromagnetism with elevating temperature). Once $ceNi$ mixes v $ceCu$ to make an alloy, this Curie temperature decreases with boosting amount the $ceCu$ (Ref.3):

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Apparently, the Curie allude has come to be $pu0 ^circ C$ or reduced for $ceCu/Ni$ alloys through compositions 67:33 or lower $ceNi$ amount. Thus, it is safe to say alloys with much less than 65% $ceNi$ in $ceCu/Ni$ alloys execute not present magnetic nature at room temperature. Therefore, the US Nickel through 25% $ceNi$ would not plot on permanent magnets.

However, Kaufmann and Starr (Ref.2) have displayed that this alloys with much less amount that $ceNi$ would obtain their your magnetism at means lower temperature (about $pu14-77 K$).

References:

E. A. Brandes, G. B. Brook, In Smithells steels Reference Book, seventh Edition; Butterworth-Heinemann: Woburn, MA, united States, 1992, chapter 11: Equilibrium Diagrams, pp. 11-236.