| Terbium Compounds |
| Terfenol-D |
Terfenol-D Tb0.3Dy0.7Fe1.9 |
| The alloy has an extremely high magnetostriction; it expands and contracts in magnetic fields. It sees application in magnetomechanical sensors, actuators, and acoustic and ultrasonic transducers or in naval sonar systems. |
| Developed in the 1950's at the Naval Ordnance Laboratory in America. It is named after terbium, iron (Fe), Naval Ordnance Laboratory (NOL), and the D comes from dysprosium. |