A. Scarfato

Multiwalled carbon nanotube films as small-sized temperature sensors

We present the fabrication of thick and dense carbon nanotube networks in the form of freestanding films (CNTFs) and the study of their electric resistance as a function of the temperature, from 4 to 420 K. A nonmetallic behavior with a monotonic R(T) and a temperature coefficient of resistance around −7×10−4 K−1 is generally observed. A behavioral accordance of the CNTF conductance with the temperature measured by a solid-state thermistor (ZnNO, Si, or Pt) is demonstrated, suggesting the possibility of using CNTFs as temperature small-sized (freely scalable) sensors, besides being confirmed by a wide range of sensitivity, fast response, and good stability and durability. Concerning electric behavior, we also underline that a transition from nonmetal to metal slightly below 273 K has been rarely observed. A model involving regions of highly anisotropic metallic conduction separated by tunneling barrier regions can explain the nonmetallic to metallic crossover based on the competing mechanisms of the metal...

Ferroelectric co-crystalline polymers

Apolar syndiotactic polystyrene (s-PS) can easily form a stable clathrate co-crystalline phase with highly polar 4-nitroaniline molecules. The ferroelectric response of thin films containing the s-PS/4-nitroaniline clathrate phase has been investigated by scanning piezoresponse force microscopy (SPFM) and compared with the response of a poly(vinylidene-fluoride-trifluoroethylene) P(VDF-TrFE) copolymer film. Measurements show that ferroelectric polymer materials can be obtained by crystalline phases whose polarity is given by low-molecular-mass guest molecules rather than by polymer chain polarity. Moreover, as for P(VDF-TrFE), nanoimprinting processes can be applied to these materials by using the SPFM technique but, in the absence of external fields, the SPFM images are lost through an exponential intensity decay.

Morphological and Structural Aspects of the Extremely Halophilic Archaeon Haloquadratum walsbyi

Ultrathin square cell Haloquadratum walsbyi from the Archaea domain are the most abundant microorganisms in the hypersaline water of coastal salterns and continental salt lakes. In this work, we explore the cell surface of these microorganisms using amplitude-modulation atomic-force microscopy in nearly physiological conditions. We demonstrate the presence of a regular corrugation with a periodicity of 16–20 nm attributed to the surface layer (S-layer) protein lattice, striped domains asymmetrically distributed on the cell faces and peculiar bulges correlated with the presence of intracellular granules. Besides, subsequent images of cell evolution during the drying process indicate the presence of an external capsule that might correspond to the giant protein halomucin, predicted by the genome but never before observed by other microscopy studies.

Local tunneling study of three-dimensional order parameter in the π band of Al-doped Mg B 2 single crystals

We have performed an extensive study of the temperature and magnetic field dependencies of local tunneling spectra measured by means of variable temperature scanning tunneling spectroscopy on high quality

Subharmonic gap structures and Josephson effect in MgB2 /Nb microconstrictions

{\mathrm{Mg}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x}{\mathrm{B}}_{2}

Observation of superconducting vortex clusters in S/F hybrids

single crystals. Single gap conductance spectra due to

Vortex Confinement in Planar Superconductor/Ferromagnet Hybrid Structures

c

Structural, electrical and magnetic characterization of artificial ferromagnetic/superconducting (La0.7Ca0.3MnO3/YBa2Cu3O7−x) heterostructures

-axis tunneling were measured, probing different amplitudes of the three-dimensional

Point Contact Spectra on YBa2Cu3O7−x/La0.7Ca0.3MnO3 bilayers

{\ensuremath{\Delta}}_{\ensuremath{\pi}}

Dimensional crossover of the charge density wave transition in thin exfoliated VSe2

as a function of Al content (i.e., as a function of the critical temperature