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Kalisky B.,Stanford University | Kalisky B.,Institute of Nanotechnology and Advanced Materials | Spanton E.M.,Stanford University | Spanton E.M.,SLAC | And 20 more authors.
Nature Materials

The ability to control materials properties through interface engineering is demonstrated by the appearance of conductivity at the interface of certain insulators, most famously the {001} interface of the band insulators LaAlO 3 and TiO 2 -terminated SrTiO 3 (STO; refs,). Transport and other measurements in this system show a plethora of diverse physical phenomena. To better understand the interface conductivity, we used scanning superconducting quantum interference device microscopy to image the magnetic field locally generated by current in an interface. At low temperature, we found that the current flowed in conductive narrow paths oriented along the crystallographic axes, embedded in a less conductive background. The configuration of these paths changed on thermal cycling above the STO cubic-to-tetragonal structural transition temperature, implying that the local conductivity is strongly modified by the STO tetragonal domain structure. The interplay between substrate domains and the interface provides an additional mechanism for understanding and controlling the behaviour of heterostructures. © 2013 Macmillan Publishers Limited. All rights reserved. Source

Zukerman R.,Ben - Gurion University of the Negev | Vradman L.,Nuclear Research Center - Negev | Titelman L.,Ben - Gurion University of the Negev | Zeiri L.,Ben - Gurion University of the Negev | And 4 more authors.
Materials Chemistry and Physics

The effect of SBA-15 microporosity on the crystal size of TiO2 was investigated employing SBA-15 materials with high (SBA-15-HM) and low (SBA-15-LM) microporosities (14.2% and 4.7% of microporous volume, respectively). TiO2 phase was incorporated inside SBA-15 using internal hydrolysis method over a wide range of loadings (7-63 wt%). At all loadings, TiO2 inside SBA-15 pores was in the form of anatase nanocrystals as found in characteristic Raman spectra. The crystal size of TiO2 anatase phase was determined by Raman spectroscopy using a correlation between Raman peak position and peak width and TiO2 crystal size. The correlation was established based on the set of unsupported TiO2 samples with the crystals size in the range 5-120 nm (BET and XRD). Using this correlation, it was found that the crystal size of TiO2 inside SBA-15 with high microporosity was lower than inside SBA-15 with low microporosity. This is a direct proof of the effect of wall microporosity on the dispersion of TiO2 inside SBA-15. Due to the higher TiO2 dispersion, TiO2/SBA-15-HM adsorbed more vanadia than TiO2/SBA-15-LM at the same TiO2 loadings. As a result, V2O5/TiO2/SBA-15-HM displayed higher activity than V2O5/TiO2/SBA-15-LM in NO SCR with ammonia. © 2010 Elsevier B.V. All rights reserved. Source

Grosz A.,Ben - Gurion University of the Negev | Mor V.,Institute of Nanotechnology and Advanced Materials | Amrusi S.,Ben - Gurion University of the Negev | Faivinov I.,Ben - Gurion University of the Negev | And 2 more authors.
IEEE Sensors Journal

Recent reports have demonstrated field resolutions of planar Hall effect magnetometers in the picotesla range. Here, we report a significant improvement in the field resolution of these sensors by decreasing their preamplifier white noise and the sensing element 1/f noise. We design, build, and test a miniature transformer-matched amplifier with a record noise level of 200 pV/ Hz and improve the fabrication process of the sensing element to increase its volume and reduce its associated 1/f noise. The magnetometer exhibits a magnetic resolution of ∼ 200 pT/ Hz at 1 Hz and ∼ 600 pT/ Hz at 0.1 Hz. These values are threefold better than previously reported results. The obtained resolution may enable applications for which high-end magnetometers, such as fluxgates, are currently used. We discuss routes for the further improvement of the magnetic field resolution. © 2016 IEEE. Source

Gottesman R.,Institute of Nanotechnology and Advanced Materials | Shukla S.,Institute of Nanotechnology and Advanced Materials | Perkas N.,Institute of Nanotechnology and Advanced Materials | Solovyov L.A.,RAS Institute of Chemistry and Chemical Technology | And 2 more authors.

Colloidal silver has gained wide acceptance as an antimicrobial agent, and various substrates coated with nanosilver such as fabrics, plastics, and metal have been shown to develop antimicrobial properties. Here, a simple method to develop coating of colloidal silver on paper using ultrasonic radiation is presented, and the coatings are characterized using X-ray diffraction (XRD), high resolution scanning electron microscope (HRSEM), and thermogravimetry (TGA) measurements. Depending on the variables such as precursor concentrations and ultrasonication time, uniform coatings ranging from 90 to 150 nm in thickness have been achieved. Focused ion beam (FIB) cross section imaging measurements revealed that silver nanoparticles penetrated the paper surface to a depth of more than 1 μm, resulting in highly stable coatings. The coated paper demonstrated antibacterial activity against E. coli and S. aureus, suggesting its potential application as a food packing material for longer shelf life. © 2010 American Chemical Society. Source

Alesker M.,Institute of Nanotechnology and Advanced Materials | Makarovsky I.,Institute of Nanotechnology and Advanced Materials | Lellouche J.-P.,Institute of Nanotechnology and Advanced Materials
Journal of Materials Chemistry

The novel reporters, unimodal FT-IR-traceable, bimodal fluorescent and FT-IR-traceable hybrid silica (SiO 2) nanoparticles (NPs), were prepared using the Stöber methodology. Initially, the basic Stöber co-hydrolysis of tetraethoxysilane (TEOS) and of the iron-complexed alkyl-triethoxysilane (EtO) 3Si-l-(η 4-2E,4E-dienyl)- Fe(CO) 3(0) (L = alkyl linker, DIT-tag reagent 3) afforded unimodal 13.7 ± 2 nm-sized SiO 2@DIT-tag 60 NPs. These NPs can incorporate an organometallic FT-IR sensitive (η 4-2E,4E-dienyl)- tricarbonyliron(0) complex moiety which acts as a sensitive FT-IR traceable species due to the strong iron complex ν FeCO vibrational bands that appear in the 1996-2063 cm -1 region, a region free of any parasitic band. The sensitivity of the FT-IR-based detection of SiO 2@DIT-tag 60 NPs has been determined using incremental mixtures of B16 melanoma cell lysates as a biological medium model. The detection limit was found to be 0.190 μg of Fe per mg of B16 cell lysate. In the second step, bimodal hybrid fluorescent and FT-IR-traceable 35.7 ± 5 nm sized SiO 2@DIT-tag 20@FITC NPs were similarly fabricated, in order to enable both fluorescence and FT-IR spectroscopy detection. This has been readily obtained through the straightforward co-incorporation of an additional fluorescein-containing alkyl-triethoxysilane conjugate FITC-APTES (FITC: fluorescein isothiocyanate, APTES: (3-aminopropyl)triethoxysilane). Subsequent surface modification with APTES of the resulting SiO 2@DIT-tag 20@FITC NPs afforded amine functionalized 34.4 ± 6 nm-sized SiO 2@DIT-tag 20@FITC@NH 2 NPs that were readily endocytosed by B16 melanoma cells. All these novel hybrid silica NPs have been fully characterized by FT-IR spectroscopy, high resolution TEM/SEM (HR-TEM/SEM) with elemental energy-dispersive X-ray spectroscopy (compositional EDAX analysis), dynamic light scattering (DLS), ζ potential measurements, and inductively coupled plasma-optical emission spectroscopy (ICP-OES). Preliminary biological studies demonstrated the non-toxicity of the NPs. No observable modification in the B16 cells' morphology or mortality was seen after the internalization of SiO 2@DIT-tag 20@FITC@NH 2 NPs. © 2011 The Royal Society of Chemistry. Source

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