Applying NiTi Shape-Memory Thin Films to Thermomechanical Data Storage Technology

2004 ◽  
Vol 855 ◽  
Author(s):  
Wendy C. Crone ◽  
Gordon A. Shaw

ABSTRACTAs 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). 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.

2011 ◽  
Vol 495 ◽  
pp. 108-111 ◽  
Author(s):  
Vasiliki P. Tsikourkitoudi ◽  
Elias P. Koumoulos ◽  
Nikolaos Papadopoulos ◽  
Costas A. Charitidis

The adhesion and mechanical stability of thin film coatings on substrates is increasingly becoming a key issue in device reliability as magnetic and storage technology driven products demand smaller, thinner and more complex functional coatings. In the present study, chemical vapor deposited Co and Co3O4thin films on SiO2and Si substrates are produced, respectively. Chemical vapor deposition is the most widely used deposition technique which produces thin films well adherent to the substrate. Co and Co3O4thin films can be used in innovative applications such as magnetic sensors, data storage devices and protective layers. The produced thin films are characterized using nanoindentation technique and their nanomechanical properties (hardness and elastic modulus) are obtained. Finally, an evaluation of the reliability of each thin film (wear analysis) is performed using the hardness to elastic modulus ratio in correlation to the ratio of irreversible work to total work for a complete loading-unloading procedure.


Author(s):  
Shunyu Chang ◽  
Yanquan Geng ◽  
Yongda Yan

AbstractAs one of the most widely used nanofabrication methods, the atomic force microscopy (AFM) tip-based nanomachining technique offers important advantages, including nanoscale manipulation accuracy, low maintenance cost, and flexible experimental operation. This technique has been applied to one-, two-, and even three-dimensional nanomachining patterns on thin films made of polymers, metals, and two-dimensional materials. These structures are widely used in the fields of nanooptics, nanoelectronics, data storage, super lubrication, and so forth. Moreover, they are believed to have a wide application in other fields, and their possible industrialization may be realized in the future. In this work, the current state of the research into the use of the AFM tip-based nanomachining method in thin-film machining is presented. First, the state of the structures machined on thin films is reviewed according to the type of thin-film materials (i.e., polymers, metals, and two-dimensional materials). Second, the related applications of tip-based nanomachining to film machining are presented. Finally, the current situation of this area and its potential development direction are discussed. This review is expected to enrich the understanding of the research status of the use of the tip-based nanomachining method in thin-film machining and ultimately broaden its application.


1990 ◽  
Vol 199 ◽  
Author(s):  
M. Libera ◽  
T. A. Nguyen ◽  
C. Hwang

ABSTRACTA number of techniques for producing TEM cross-sections of thin films have been described in recent years as the need for improved and more-thorough microstructural study of thin-film materials has grown. We have developed a method for producing such cross-sections which involves little sophisticated equipment other than an ion mill for thinning. Following the method of Bravman and Sinclair (J. Elec. Micrs. Tech 1,53–61 (1984)), the film of interest is either deposited on or epoxied to a silicon wafer and a composite of six silicon beams (=3mm × 25mm × 0.5mm) is fabricated. Slices are cut from this composite perpendicular to the film plane, and each slice is mechanically thinned by a series of simple grinding and polishing steps to ∼ 50–100μm. Dimpling is not necessary. The specimen is mounted onto a slotted TEM grid which provides a vehicle for safe handling, and the specimen is ion milled to perforation. We have found the technique to be relatively fast, reliable, and simple. Its success hinges on minimizing the amount of direct handling required when the specimen is thin and fragile. We present a detailed recipe describing its various steps and show typical results from studies of thin films for data-storage applications.


2008 ◽  
Vol 130 (10) ◽  
Author(s):  
Ankur Jain ◽  
Kenneth E. Goodson

An accurate measurement of the thermophysical properties of freestanding thin films is essential for modeling and predicting thermal performance of microsystems. This paper presents a method for simultaneous measurement of in-plane thermal conductivity and heat capacity of freestanding thin films based on the thermal response to a sinusoidal electric current. An analytical model for the temperature response of a freestanding thin film to a sinusoidal heating current passing through a metal heater patterned on top of the thin film is derived. Freestanding thin-film samples of silicon nitride and nickel titanium (NiTi), a shape memory alloy, are microfabricated and characterized. The thermal conductivity of thin-film NiTi, which increases linearly between 243K and 313K, is 40% lower than the bulk value at room temperature. The heat capacity of NiTi also increases linearly with temperature in the low temperature phase and is nearly constant above 280K. The measurement technique developed in this work is expected to contribute to an accurate thermal property measurement of thin-film materials. Thermophysical measurements on NiTi presented in this work are expected to aid in an accurate thermal modeling of microdevices based on the shape memory effect.


2003 ◽  
Vol 76 (6) ◽  
pp. 879-884 ◽  
Author(s):  
M.R. Koblischka ◽  
B. Hewener ◽  
U. Hartmann ◽  
A. Wienss ◽  
B. Christoffer ◽  
...  

2002 ◽  
Vol 750 ◽  
Author(s):  
D. S. Grummon ◽  
R. Gotthardt ◽  
T. LaGrange

ABSTRACTAlthough slow and dissipative, sputtered thin-film shape-memory alloys like equiatomic titanium-nickel can exert a large ohmically-excited force displacement product when deployed in photolithographically micromachined actuators. They give energy densities far exceeding those typically produced by competing microactuator materials [1], and their size can probably be scaled down to the nanometer range (where the benefits of high surface to volume ratio are best exploited for speed and efficiency). But a large, energetic, and resettable actuation stroke is possible only if some agency has imparted a non-trivial initial plastic strain, of between one and five percent, to the martensite phase. Is not always obvious how this strain is to be achieved when discrete mechanical manipulation of the active element is difficult. Furthermore, for cyclic actuation, a resetting-force that periodically re-deforms the martensite during the cooling interval must arise naturally from mechanical elements in the design. Here, several methods responding these requirements are discussed in relation to various kinematic themes.


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