Question

A proton has spin and magnetic moment just like an electron. Why then its effect is neglected in magnetism of materials?

Answer 1

Formula used: $\mu =\frac{eh}{4\pi m}$

The spin of a proton and electron can be compared by their magnetic dipole moment.

Magnetic moment of proton, ${\mu }_P=\frac{eh}{4\pi m_p}$

And magnetic moment of electron,${\mu }_e=\frac{eh}{4\pi m_e}$

$\Rightarrow \frac{{\mu }_P}{{\mu }_e}=\frac{m_e}{m_p}$

As we know, $m_p>>m_e$

${\mu }_P<<{\mu }_e$

Therefore, magnetic moment of proton is neglected as compared to that of electron.

Final answer: Due to higher mass of proton.