Magnetism, at its root, arises from three sources: Electric current Spin magnetic moments of elementary particles Changing electric fields The magnetic properties of materials are mainly due to the magnetic moments of their atoms' orbiting electrons. The magnetic moments of the nuclei of atoms are typically thousands of times smaller than the electrons' magnetic moments, so they are negligible in the context of the magnetization of materials. Nuclear magnetic moments are nevertheless very important in other contexts, particularly in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI).
mAGnetism, aT ItS rOot, arIseS fRom ThrEe sourcEs: electRIc current spIn mAgnetiC momentS of elEmeNtarY particles chanGinG eLEcTric fields The MaGnEtIc properTIes Of matErials ArE Mainly DUE to THe magNetic momentS oF theIr atoms' Orbiting ElectROns. the magNetic MOments Of the nUcLEi Of aToms arE TypiCAlLY ThousAnDs of tiMeS SMalLer than the eLeCTrOnS' MagnEtIc momenTs, So they Are negligibLe iN tHe ContexT oF thE MagnetIZatION of matErials. nuclEar mAGnETic MOmenTS ArE neVErtHElEss vEry impoRtaNt iN OTHer contexTs, pARticulaRly In nuclear magnEtic ResOnance (nMR) and MAgneTIC reSonaNce IMAging (mri).