DIGITAL STORAGE DEVICE USING THIN-FILM SHAPE-MEMORY ALLOY

THE NEED FOR HIGH VOLUME, HIGH SPEED DIGITAL DATA RECORDING,STORAGE AND RETRIEVAL SYSTEMS IS GROWING RAPIDLY. OVER THE PAST DECADE QUANTUM INCREASES IN STORAGE CAPACITY AND DATA TRANSFER RATES HAVE BEEN MET BY STILL GREATER DEMAND. MAGNETIC MEDIA TECHNOLOGY IS APPROACHING ITS PRACTICAL LIMITS OF CAPACITY WHILE EXISTING WORK ON OPTICAL MEDIA SEEMS TO BE LIMITED TO MAGNETO-OPTICAL AND WORM (WRITE ONCE, READ MANY TIMES) TECHNOLOGY. THERE IS A CLEAR NEED TO INCREASE THE SPEED AND CAPACITY OF MASS STORAGE SYSTEMS, NOT ONLY FOR ROUTINE SCIENCE, ENGINEERING AND BUSINESS SYSTEMS, BUT FOR EXISTING AND FUTURE SUPERCOMPUTERS. OPTICAL READ-WRITE-ERASE WHICH EXTEND THE DENSITY OF INFORMATION STORAGE TO THE LIMITS OF OPTICAL DIFFRACTION OFFER A VERY PROMISING AREA OF INVESTIGATION. IT IS PROPOSED THAT A THIN FILM OF SHAPE-MEMORY ALLOY SUCH AS NITINOL (NICKEL-TITANIUM ALLOY) BE USED AS A MEDIUM FOR HIGH-DENSITY NON-VOLATILE READ-WRITE DIGITAL INFORMATION STORAGE. SMALL DOMAINS (APPROACHING ONE MICRON IN DIAMETER) OF SHAPE-MEMORY ALLOY ARE SELECTIVELY HEATED BY FAST, HIGH-INTENSITY LIGHT PULSES CAUSING THE DOMAINS TO CHANGE THEIR ANGLE AND/OR AMOUNT OF REFLECTANCE. READOUT IS ACCOMPLISHED BY DETECTION OF REFLECTED PULSES OF LIGHT OF LOWER INTENSITY FROM THE SMALL DOMAINS. THE PROPOSED PHASE I RESEARCH SHOULD ANSWER THE FOLLOWING THREE CRITICAL QUESTIONS: 1) WILL SHAPE-MEMORY ALLOYS MAINTAIN THEIR DESIREABLE AND NECESSARY PHYSICAL PROPERTIES WHEN APPLIED TO APPROPRIATE SUBSTRATES AS THIN FILMS? 2) WHICH SHAPE-MEMORY ALLOYS, AT WHAT THICKNESSES, AND ON WHAT SUBSTRATE COMPOSITION WILL HAVE THE MOST DESIREABLE ANDUSEFUL CHARACTERISTICS? 3) WHAT DATA RECORDING/READING (READ-WRITE-ERASE) METHOD WILL BE THE MOST EFFECTIVE?