▁earth ▁met als ▁as ▁strateg ically ▁important , ▁ ▁and ▁recent ▁Chinese ▁export ▁restrictions ▁on ▁these ▁materials ▁have ▁led ▁some ▁to ▁initi ate ▁research ▁programs ▁to ▁develop ▁strong ▁magnet s ▁that ▁do ▁not ▁require ▁rare ▁earth ▁met als . ▁ ▁Ex plan ation ▁of ▁strength ▁ ▁The ▁rare - ear th ▁( lan than ide ) ▁elements ▁are ▁met als ▁that ▁are ▁fer romagnet ic , ▁meaning ▁that ▁like ▁iron ▁they ▁can ▁be ▁magnet ized ▁to ▁become ▁permanent ▁magnet s , ▁but ▁their ▁Cur ie ▁temper atures ▁( the ▁temperature ▁above ▁which ▁their ▁fer romagnet ism ▁disapp ears ) ▁are ▁below ▁room ▁temperature , ▁so ▁in ▁pure ▁form ▁their ▁magnet ism ▁only ▁appears ▁at ▁low ▁temper atures . ▁However , ▁they ▁form ▁comp ounds ▁with ▁the ▁transition ▁met als ▁such ▁as ▁iron , ▁nick el , ▁and ▁c ob alt , ▁and ▁some ▁of ▁these ▁comp ounds ▁have ▁Cur ie ▁temper atures ▁well ▁above ▁room ▁temperature . ▁ ▁R are - ear th ▁magnet s ▁are ▁made ▁from ▁these ▁comp ounds . ▁ ▁The ▁greater ▁strength ▁of ▁rare - ear th ▁magnet s ▁is ▁mostly ▁due ▁to ▁two ▁factors : ▁ ▁First , ▁their ▁cry st all ine ▁structures ▁have ▁very ▁high ▁magnetic ▁an is ot ropy . ▁This ▁means ▁that ▁a ▁cry stal ▁of ▁the ▁material ▁prefer entially ▁magnet izes ▁along ▁a ▁specific ▁cry stal ▁axis ▁but ▁is ▁very ▁difficult ▁to ▁magnet ize ▁in ▁other ▁directions . ▁▁ ▁Like ▁other ▁magnet s , ▁rare - ear th ▁magnet s ▁are ▁composed ▁of