We have proposed new magnetic memories using parallel-aligned nanowires without mechanical moving parts, in order to achieve the ultra high transfer rate of more than 144 Gbps for Super Hi-Vision TV. In the magnetic memory using nanowires, the data are stored as the magnetic domains with up or down magnetization in magnetic nanowires, and the domains are shifted quite faster by applying optimum current along the nanowire direction for data writing and reading purpose. Since the electric circuits and the insulation space between the neighbor nanowires are necessary for moving the magnetic domain walls, the areal recording density is essentially reduced as compared with that of conventional hard disk drives. In this study, in order to increase the areal recording density of magnetic nanowire memory, we have tried to act one magnetic nanowire as the virtual multiple data tracks. The shallow scratched trench was introduced using scanning probe microscopy along the length direction on the surface of a single nanowire to form multiple internal tracks, and we have succeeded in realizing a couple of virtual tracks states.

Living neuronal cells present active mechanical structures which evolve with cellular growth and changes in the cell microenvironment. Detailed knowledge of various mechanical parameters such as cell stiffness or adhesion forces and traction stresses generated during axonal extension is essential for understanding the mechanisms that control neuronal growth, development and repair. Here we present a combined Atomic Force Microscopy (AFM)/Fluorescence Microscopy approach for obtaining systematic, high-resolution elasticity and fluorescent maps for live neuronal cells. This approach allows us to simultaneously image and apply controllable forces to neurons, and also to monitor the real time dynamics of the cell cytoskeleton. We measure how the stiffness of neurons changes both during axonal growth and upon chemical modification of the cell, and identify the cytoskeletal components most responsible for the changes in cellular elasticity. This is accomplished by identifying cellular components with unique elastic signatures, and tracking those components over time within healthy cells or within cells treated to disrupt selective components.

Various nanostructures with high-aspect-ratio formed in a low-resistivity silicon wafer by the nano-processing using a carbon nanotube (CNT) probe of a scanning tunneling microscope (STM) have been investigated. The multi-wall CNT probes were obtained with our original pulling-method from CNT dispersion liquid. Nanostructures of point configurations (pit and mound) and line configurations were obtained at the constant tunneling current of 0.1 nA by controlling the bias voltages up to 10 V, processing times up to 300 s and scanning speeds of probe up to 480 nm/s for a line configuration. The aspect-ratio of the pit configuration fabricated at the bias voltage of 3 V increased about 6 times in proportion to the increase in processing time. Remarkable influence of the bias voltage on the configurations indicated that there exists a threshold bias voltage for the transition from the pit configuration to the mound one between 3 V and 5 V, and the aspect ratio of all nanostructures fabricated by the CNT probe were larger than those by a conventional tungsten probe. Finally, cross-sectional TEM observations were also applied to clarify the difference in the formation mechanisms between the pit configuration and the mound configuration. The TEM image of the pit configuration showed neither dislocations nor remarkable strains existed, but in the case of the mound shape TEM analysis indicated the existence of single crystalline silicon region solidified with atomic defects under the mound configuration. Therefore the drastic change of the configurations was attributed to the changes of the atomic-scale microstructures by applying the bias voltages.

A new three-dimensional cell shape index using the AFM height images of cells cultured on cell substrates was defined. The new cell shape index revealed quantitative cell spreading information of cells that is not included in the conventional cell shape index. The quantitative morphometry of rat cerebral cortical astrocytes cultured on four different kinds of cell substrates were investigated using the conventional and the new cell shape index, and the results were compared. The new cell shape index showed the quantitative astrocyte spreading and stellation behavior that agrees with the AFM height images of astrocytes.

This report outlines a methodology for reading back different electrical charges, from Non Volatile Memory (NVM) based Flash devices. The charge is stored in the floating gates (FGs) of the transistors. Reading back these charges in the form of logic levels of “1 bit (1b)” and “0 bit (0b)” without deleting the information from the device was the goal. Scanning Capacitance Microscopy (SCM) with ∼50-100 nm spatial resolution was used, to directly probe the charge on Floating Gate Transistor (FGT) channels. Transistor charge values (ON/OFF or “1b/0b”) are measured. Both the sample preparation and SCM probing methods are discussed. The application has been demonstrated with SanDisk based 64 MB NAND Flash memory device.

Metal films on polymer substrates are commonly used in flexible electronic devices and as gas barrier coatings. One way to evaluate the fracture and adhesion properties of such film systems is the fragmentation test. In the fragmentation test a film-substrate system is strained in tension under an optical microscope or inside a scanning electron microscope to observe the cracking and delamination events in situ. The technique works very well for brittle metal and ceramic films. However, when ductile films are strained they deform plastically before cracks and buckles appear. Therefore, a tensile straining device was developed to fit under an AFM for in situ observation of ductile metal films on polymer substrates. With the new in situ device the first occurrence of plastic deformation in the form of localized thinning of the film and channel cracks are visible. These features can only be detected through a height difference in the AFM images and not with optical or scanning electron micrographs. A comparison to brittle Cr films on polymer substrates was performed.

Protein adsorption is the first phenomenon which occurs at nanoscale level when a given surface came into contact with a living fluid cell such as blood. Investigation of this adsorption at nanoscale provides useful information about kinetics and mechanism of conformation of proteins on a given surface. The present study investigates the adsorption of proteins using tapping/intermittent mode atomic force microscopy (T-AFM). The approach taken here is that hydrogenated amorphous carbon coating (a-C:H) is used as a model surface because it is amorphous, smooth, inert and hydrophobic. Two proteins namely albumin and fibrinogen in phosphate buffer (PBS) and de-ionized water are drop casted to study the adsorption kinetics. First and second resonance AFM data was used to investigate the adsorbed layer of proteins. AFM force curve and scratch experiment were used to verify the adhesion and thickness of the adsorbed layer. Combination of height, phase images along with the AFM force curve and scratch experiment shows inhomogeneous distribution of albumin protein in phosphate buffer compared to other protein solutions.

Several examples of Atomic Force Microscopy imaging in the oscillatory resonant and non-resonant modes are analyzed with a theoretical description of tip-sample force interactions. The problems of high-resolution imaging and compositional mapping of heterogeneous polymers are considered. The interplay with theory helps the experiment optimization and rational understanding of the image contrast.

Scanning Tunneling Microscope (STM) was used to examine the morphologies of selfassembled InGaAs quantum dots (QDs). In order to induce the self-assembly, unlike the conventional Stranski-Krastanov (S-K) growth method, spatial thermal modulations in nanoscale were created in-situ on strained-but-flat InGaAs surfaces in a Molecular Beam Epitaxy (MBE) growth reactor by applying interferential irradiations of laser pulses (IILP). As-irradiated surfaces were examined using an attached ultra-high vacuum (UHV) STM. STM images indicate that the irradiation of 7 nano second laser pulse induces self-assembly of QDs. The average size of laser-induced QDs is smaller while their density is larger than that of QDs formed by annealing strained but flat epilayers conventionally. Furthermore, the dot density is modulated sinusoidally with a periodicity commensurate with that of the interference, which suggests that the placement of QDs can be controlled on the scale of the optical wavelength used. QD volume analysis suggests that dots grow faster laterally than vertically so that dots become flattened as they get larger.