BiFeO3 (BFO) films were grown on LaNiO3-coated Si substrate by a RF magnetron sputtering system at temperatures in the range of 300-700 °C. X-ray reflectivity and high-resolution diffraction measurements were emp...
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作者：
Li ZengErik HelgrenHayo ZutzCarsten RonningFrances Hellmanli_zeng@berkeley.edu
University of California San Diego Materials Science and Engineering Program 2306 Roosevelt Ave. Berkeley CA 94703 United States 510-643-4112 510-643-8497 helgren@berkeley.edu
University of California Berkeley Physics Department 366 Le Conte Berkeley CA 94720 United States hzutz@gwdg.de
University of Göttingen II. Institute of Physics Friedrich-Hund-PLatz 1 Gottingen N/A 37077 Germany Carsten.Ronning@phys.uni-goettingen.de
University of Göttingen II. Institute of Physics Friedrich-Hund-PLatz 1 Gottingen N/A 37077 Germany fhellman@berkeley.edu
University of California Berkeley Physics Department 366 Le Conte Berkeley CA 94720 United States
Tetrahedrally bonded amorphous carbon (ta-C) thin films were prepared by mass selected ion beam deposition (MSIBD) using 100 eV carbon ions at room temperature. Gadolinium, a magnetic rare earth element, was implanted...
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Tetrahedrally bonded amorphous carbon (ta-C) thin films were prepared by mass selected ion beam deposition (MSIBD) using 100 eV carbon ions at room temperature. Gadolinium, a magnetic rare earth element, was implanted as a dopant into ta-C with two different fluences. The doping level of the ta-C:Gdx layers was in maximum 4 or 7 at.%, respectively. The Gd is believed to be electrically activated in as-implanted films, although contributions from the sp2 sites cannot be ruled out. A transition temperature (T') was found, below which there is a large negative magnetoresistance (MR) with a strong temperature dependence. Thermal annealing greatly increases the sample conductivity due to the increase of sp2 sites. However, the MR persists at least up to an annealing temperature of 500°C. Magnetically, the Gd dopants behave like non-interacting local moments. Similarities and differences in physical properties between the ta-C:Gdx films and other Gd doped amorphous semiconductors are compared.
The origin of the functional properties of complex oxide superlattices can be resolved using time-resolved synchrotron x-ray diffraction into contributions from the component layers making up the repeating unit. The C...
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The origin of the functional properties of complex oxide superlattices can be resolved using time-resolved synchrotron x-ray diffraction into contributions from the component layers making up the repeating unit. The CaTiO3 layers of a CaTiO3/BaTiO3 superlattice have a piezoelectric response to an applied electric field, consistent with a large continuous polarization throughout the superlattice. The overall piezoelectric coefficient at large strains, 54 pm/V, agrees with first-principles predictions in which a tetragonal symmetry is imposed on the superlattice by the SrTiO3 substrate.
In this study, polycardanol, which was synthesized by enzymatic oxidative polymerization of thermally treated cashew nut shell liquid (CNSL) using fungal peroxidase, was partially or fully cured using methyl ethyl ket...
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Amorphous oxide semiconductor memory devices with HfInZnOx as the channel layer and high k dielectric stacks as the charge storage medium were fabricated. HfO2 and Al2O3 and HfAlOx films were examined as the charge tr...
Amorphous oxide semiconductor memory devices with HfInZnOx as the channel layer and high k dielectric stacks as the charge storage medium were fabricated. HfO2 and Al2O3 and HfAlOx films were examined as the charge trap layers. The drain current - gate voltage transfer curves of the fabricated charge trap memories show a large hysteresis due to the electron trapping and de-trapping at the interfaces between the high-k charge storage layer and the SiO2. The device structure and operational scheme for the amorphous oxide semiconductor charge trap memories were suggested based on these properties.
There remains considerable interest in the behavior of acceptors in ZnO, the ultimate goal being the realization of device grade p-type material. Silver is a candidate acceptor, and, in this study, in situ doping of s...
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We have been developing a new approach to layered hybrid (inorganic/organic) photovoltaic materials for fabrication by Roll-to-Roll (R2R) manufacturing. In this report, we combine the low cost and processability of or...
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Compositional lipid microdomains (“lipid rafts”) in mammalian plasma membranes are believed to facilitate many important cellular processes. While several physically distinct scenarios predicting the presence of fin...
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Compositional lipid microdomains (“lipid rafts”) in mammalian plasma membranes are believed to facilitate many important cellular processes. While several physically distinct scenarios predicting the presence of finite-sized microdomains in vivo have been proposed in the past, direct experimental verification or falsification of model predictions has remained elusive. Herein, we demonstrate that the combination of the spatial correlation and temporal fluctuation spectra of the lipid domains can be employed to unambiguously differentiate between the existing theoretical scenarios. Furthermore, the differentiation of the raft formation mechanisms using this methodology can be achieved by collecting data at physiologically relevant conditions without the need to tune control parameters.
Compositional lipid domains (lipid rafts) in plasma membranes are believed to be important components of many cellular processes. The mechanisms by which cells regulate the sizes, lifetimes, and spatial localization o...
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Compositional lipid domains (lipid rafts) in plasma membranes are believed to be important components of many cellular processes. The mechanisms by which cells regulate the sizes, lifetimes, and spatial localization of these domains are rather poorly understood at the moment. We propose a robust mechanism for the formation of finite-sized lipid raft domains in plasma membranes, the competition between phase separation in an immiscible lipid system and active cellular lipid transport processes naturally leads to the formation of such domains. Simulations of a continuum model reveal that the raft size distribution is broad and the average raft size is strongly dependent on the rates of cellular and interlayer lipid transport processes. We demonstrate that spatiotemporal variations in the recycling may enable the cell to localize larger raft aggregates at specific parts along the membrane. Moreover, we show that membrane compartmentalization may further facilitate spatial localization of the raft domains. Finally, we demonstrate that local interactions with immobile membrane proteins can spatially localize the rafts and lead to further clustering.
The interest to silicon-diamond structures was recently renewed motivated by industry's needs for composite substrates and better thermal management. In this work we investigated thermal conductivity and thermal b...
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The interest to silicon-diamond structures was recently renewed motivated by industry's needs for composite substrates and better thermal management. In this work we investigated thermal conductivity and thermal boundary resistance (TBR) of ultrananocrystalline (UNCD) and microcrystalline diamond (MCD) films on silicon. The measurements were carried out using the transient plane source (TPS) technique. It was found that most of the silicon-synthetic heterostructures are rather resistive thermally with the TBR values of up to ~10 -6 m 2 K/W at room temperature. We established an importance of the trade-off between the structures characterized by the ultra-small diamond grain size with smooth silicon-diamond interface and those with larger grain size but rougher interface. It is shown that composite Si/Diamond wafers are promising at the elevated temperatures characteristic for operation of state-of-art electronic devices. The knowledge of TBR and heat conduction through silicon - diamond heterostructures is important for further development of composite substrates for electronic and optoelectronic industries.
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