We have been researching long lasting magnetic properties for use in the Clock of the Long Now. Magnetite or lodestone is a naturally occurring magnetic material that has been known for at least two millennia. These materials have held their magnetism even over geologic time scales which makes them interesting for potential use in the Clock. We could potentially use them for actuating/holding without touching thus eliminating wear. I just came across this article on a new property some nano-tech engineers came across when they super cooled magnetite and made it change states into a conductor. I like that such an old material is finding new use in the nano-tech world…
With engineers looking to exploit novel electronic materials for next-generation computers and hard drives, phase transitions between insulating and conducting states have become an increasingly hot research topic in physics and materials science in recent years.
The debate about the causes and specifics of magnetite’s temperature-driven phase change has simmered much longer. Natelson said physicists have long sparred about the possible underlying physical and electronic causes of the phase transition. The discovery of this new voltage-driven switching provides new clues, but more research is still needed, he said.
“The effect we discovered probably wasn’t noticed in the past because nanotechnology is only now making it possible to prepare the electrodes, nanoparticles, and thin films required for study with the precision necessary to document the effect,” he said.