# Is anisotropic radioactivity really impossible?

What if the nucleus has a magnetic moment, and also the electron shell has one? I suspect, in this case, the orientation of the nucleus could be "fixed" by the electron shell.

Maybe a mono-crystal of such a material would have an anisotropic radioactivity. Thus, its radioactivity wouldn't be the same in all directions.

I think, relative many requirements should be fulfilled:

• The nucleus must be radioactive.
• It must have a magnetic moment.
• The electron shell must have also a magnetic moment.
• The orientations of the atoms in the crystal structure should be unidirectional.

Is it possible? Does any such crystal already exist? Maybe the crystal of a radioactive isotope of some ferromagnetic element could fulfill all of these?

If not, why not?

• Your best guess is probably a neutron star. – CuriousOne Jun 18 '16 at 9:06
• @CuriousOne :-) Well, currently I am thinking on laboratory-sized mono-crystalls. :-) – user259412 Jun 18 '16 at 9:26

Chien-Shiung Wu at the US National Bureau of Standards prepared a thin surface of ${}^{60}Co$. This isotope decays by beta decay, producing one electron and one antineutrino. Due to the small magnetic moment of the nuclei, they had to cool the surface to 0.003 K, and then the sample was magnetized in an uniform magnetic field.