| NiTi Shape-Memory Thin Films: The Potential for Thermomechanical Data Storage Technology | ||
| Prof. Wendy C. Crone1, Dr. Gordon A. Shaw2 and Mr. Rui M. S. Martins3, 1Engineering Physics, Univesrity of Wisconsin - Madison, 1500 Engineering Drive, Madison, WI 53706, 2Manufacturing Metrology, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, 3Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, Dresden, 01314, Germany As the data storage density in cutting edge microelectronic devices continues to increase, the superparamagnetic effect poses a problem for magnetic data storage media. One strategy for overcoming this obstacle is the use of thermomechanical data storage technology. In this approach, data is written by a nanoscale mechanical probe as an indentation on a surface, read by a transducer built into the probe, and then erased by the application of heat. An example of such a device is the IBM millipede which uses a polymer thin film as the data storage medium. It is also possible, however, to use other kinds of media for thermomechanical data storage, and in the following work, we explore the possibility of using thin film Ni-Ti shape memory alloy (SMA). Because of its robustness, high work density, amenability to thin film deposition, and capacity for electrical activation through resistive heating, NiTi would seem to be an ideal choice for nanoscale actuation. Previous work has shown that nanometer-scale indentations made in martensite phase Ni-Ti SMA thin films recover substantially upon heating. Issues such as repeated thermomechanical cycling of indentations, indent proximity, and film thickness impact the practicability of this technique. While there are still problems to be solved, the experimental evidence and theoretical predictions show SMA thin films are an appropriate medium for thermomechanical data storage. | ||