Coherent Diffractive Imaging (CDI) is an algorithmic imaging technique where intricate features are reconstructed from measurements of the freely diffracting intensity pattern. An important goal of such lensless imaging methods is to study the structure of molecules that cannot be crystallized. Ideally, one would want to perform CDI at the highest achievable spatial resolution and in a single-shot measurement such that it could be applied to imaging of ultrafast events. However, the resolution of current CDI techniques is limited by the diffraction limit, hence they cannot resolve features smaller than one half the wavelength of the illuminating light. Here, we present sparsity-based single-shot subwavelength resolution CDI: algorithmic reconstruction of subwavelength features from far-field intensity patterns, at a resolution several times better than the diffraction limit. This work paves the way for subwavelength CDI at ultrafast rates, and it can considerably improve the CDI resolution with X-ray free-electron lasers and high harmonics.

The structure of cobalt formed by electrodeposition and the influence of the pH of the plating solution and the cathode potential was studied by potentiodynamic measurements and X-ray diffraction. It was found that the level of overpotential significantly affects the structure of the formed cobalt. When electrodeposition is performed far from equilibrium conditions, i.e., at a high overpotential, face-centered cubic ͑fcc͒ cobalt is deposited while at low overpotential hexagonal close packed Co is formed with a lower rate of hydrogen evolution. A higher overpotential is needed in a neutral compared to acidic solution in order to enhance the evolution of hydrogen that is required for the formation of fcc cobalt.There is a growing interest in magnetic thin films, especially in cobalt films, due to their wide range of application as magnetic data storage devices. 1-5 These films are usually prepared by physical deposition methods which require ultrahigh vacuum techniques. [6][7] An alternative processing technique is electrodeposition. Electrodeposition has several advantages over dry processes. 8 Electrodeposition does not require vacuum technology and consequently is less expensive. It can easily be upscaled for use in large size areas, and it is capable of depositing uniform films on complex surfaces without the shadowing effects often encountered in other deposition methods. The experimental systems used are much simpler than evaporation or sputtering apparatus, and electrodeposition can be a room-temperature technology. However, there are some drawbacks associated with the process, such as the need for a conducting/ semiconducting substrate, the limited number of elements that can be deposited, and the large number of variables that influence this process ͑composition, pH, concentration, current density, temperature, agitation, etc.͒.Hexagonal close packing ͑hcp͒ is the usual structure for electroplated cobalt. It is also known, 9 that face-centered cubic ͑fcc͒ cobalt, which is stable at temperatures above 422°C, can sometimes be obtained from electrodeposition at ambient temperatures. Gelchinski et al. 10 have electroplated, at room temperature, cobalt-chromium alloys containing the cP8 structure type, 11,12 that is stable only at high temperatures, according to the equilibrium phase diagram.Several researchers 9,13-22 have reported that the pH of the bath solution significantly affects the structure of cobalt formed by electrodeposition. A solution with a low pH (Ͻ2.5) was reported to favor fcc cobalt, 9,13-22 whereas a high pH (Ͼ2.5) or a high temperature system favored the formation of hcp cobalt in a sulfate bath with no organic additives. 14 Agitation of a sulfate bath also favored hcp cobalt. A high deposition temperature in a chloride bath also induced the formation of hcp cobalt, 17,18 whereas high current densities in sulfamate solutions were found to favor the cubic structure. 19 In addition, a high degree of preferred orientation has been observed by Sard et al. 18 for cobalt formed in sulfate baths....

Electrodeposition characteristics of Cu-Co films were studied for the formation of heterogeneous alloys for giant magnetoresistance applications. In situ scanning tunneling microscopy, Auger electron spectroscopy ͑AES͒, and high resolution scanning electron microscopy studies showed that rough films with a low concentration of cobalt ͓Cu92.5-Co7.5͔ ͑atom %͒ were deposited mainly due to a higher deposition rate of copper than of cobalt toward the end of the deposition process, and due to the formation of copper grains after the electrodeposition process by chemical exchange between copper ions in the solution and with the cobalt in the deposit. AES analysis revealed that the Cu-Co film is not homogeneous; the bulk of the film is richer in Co while the surface and the bottom of the film are Co-poor. X-ray diffraction showed that the electrodeposition is a topotaxial crystallization process and that the as-deposited film is composed of two phases, a solid solution of face centered cubic Cu-Co with preferred orientation of ͕111͖ planes, and a hexagonal close packed Co phase. Scanning electron microscopy micrographs and energy dispersive spectroscopy indicated the segregation of cobalt grains resulting from thermal treatments, according to the phase diagram of Cu-Co.One of the most exciting and startling properties exhibited by some magnetic multilayer systems is the giant magnetoresistance ͑GMR͒ effect. GMR refers to a significant change in the electrical resistance of a film or a device when an external magnetic field is applied. The GMR effect which was first discovered in magnetic multilayers 1 also exists in heterogeneous alloys with ferromagnetic granules ͑i.e., Fe or Co͒ embedded in a nonmagnetic metal ͑i.e., Cu or Ag͒. 2 Heterogeneous alloy films are a potentially useful alternative for GMR applications, especially for magnetic sensor applications, where the sensitivity is less important than the magnitude of the response. 2 It is generally simpler to prepare a heterogeneous alloy film rather than a multilayer system. The heterogeneous alloy films are immiscible combinations usually prepared by physical deposition methods. 3,4 An alternative processing technique is electrodeposition. 5-13 Electrodeposition has several advantages over dry processes. There are a large number of possible alloy combinations. Electrodeposition does not require vacuum technology and consequently is less expensive. It can easily be scaled up for use in large size areas, and it is capable of depositing uniform films on complex surfaces without shadowing effects often encountered in other deposition methods. The experimental systems used are much simpler than evaporation or sputtering apparatus, and electrodeposition can be a roomtemperature technology. There are some drawbacks associated with the process such as the need for a conducting/semiconducting substrate, the limited number of elements that can be deposited, and the large number of variables that control this process ͑composition, pH, concentration, current density, temperatur...

We demonstrate a low voltage nonvolatile memory field effect transistor comprising thermal SiO2 tunneling and HfO2 blocking layers as the gate dielectric stack and Au nanocrystals as charge storage nodes. The structure exhibits a memory window of ∼2 V at an applied sweeping voltage of ±3 V which increases to 12.6 at ±12 V. Retention tests show an extrapolated loss of 16% after ten years in the hysteresis width of the threshold voltage. Dynamic program/erase operation reveal an approximately pulse width independent memory for pulse durations of 1 μs to 10 ms; longer pulses increase the memory window while for pulses shorter than 1 μs, the memory windows vanishes. The effective oxide thickness is below 10 nm with very low gate and drain leakage currents.

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