Amorphous Heusler Alloys As Magneto-Optic Recording Materials
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
Heusler alloys including Cu2NbIn, Cu2MnAl, and Cu2MnSn can be prepared as amorphous films when sputtered onto liquid nitrogen-cooled substrates under certain bias conditions . The films are non-magnetic, but when annealed at 200 C, they crystallize into their normal cubic structures in which the interatomic distances allow positive exchange forces to dominate, and ferro-magnetism results. When amorphous Heusler alloys are prepared in this way, they can be used as magneto-optical recording materials. The amorphous Heusler alloy is sputtered onto a disc and then laser annealed to its magnetic crystalline form with a HeNe laser. The annealed spot requires only a brief exposure at 200ŒC, requiring little power. If Curie point recording is used, the temperature should reach about 260ŒC.