Rare-earth elements are those 30 metals found in the periodic table's oft-omitted center two rows. They're used in many modern applications.
Most powerful magnets
Magnets made of rare-earth metals are particularly powerful alloys with crystalline structures that have high magnetic anistropy — which means that they readily align in one direction, and resist it in others. Discovered in the 1940s and first identified and defined by Karl J. Strnat and G. Hoffer in 1966, rare-earth magnets are one-third to two times more powerful than traditional ferrite magnets — generating fields up to 1.4 Teslas in some cases.
Rare-earth metals are used in rechargable batteries, catalytic converters, guided munitions, LCD and plasma displays, and aerospace superalloys.
Their magnets are used in MRI machines, portable electronic devices, hysteresis clutches, accelerometers, and permanent-magnet rotary and linear motors.