Radioactivity and Magnetism

Most recent answer: 10/22/2007

Does radioactivity have any affect on magnetism? THANKS
- Zach
No, not really; radioactivity and magnetism are rather different things.

That having been said, radioactivity and magnetism do show up together in various contexts, and there are some things which are interesting to talk about.

Some forms of radioactivity (alpha and beta emission, to be specific) involve the emission of charged particles from atoms which decay. In alpha decay, a helium nucleus, two protons and two neutrons, is ejected from the decaying atom. In beta emission, it is an electron which is emitted. A magnetic field will change the flight paths these charged particles will follow as they escape the atom, bending them around in circles, or more generally, helixes (think of a slinky spring -- that’s the shape of a helix. A DNA molecule has two intertwined helixes).

Another way radioactivity may have something to do with magnetism is to transform a magnetic material into another via the process of radioactive decay. 55Fe is an unstable isotope of iron which decays by an interesting process. The nucleus combines with one of the inner-shell electrons, turning a proton into a neutron, and emitting a neutrino in the process. The electrons then rearrange themselves (one’s missing, so another falls down to to take its place), emitting a gamma ray. The resulting atom is manganese, which is not ferromagnetic by itself, but can be combined with other metals to make ferromagnetic alloys. If you start with a pure lump of magnetized 55Fe and wait a decade or so, the lump will mostly have turned into much less magnetic manganese.


(published on 10/22/2007)

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