66 research outputs found
Out of equilibrium electronic transport properties of a misfit cobaltite thin film
We report on transport measurements in a thin film of the 2D misfit Cobaltite
. Dc magnetoresistance measurements obey the modified
variable range hopping law expected for a soft Coulomb gap. When the sample is
cooled down, we observe large telegraphic-like fluctuations. At low
temperature, these slow fluctuations have non Gaussian statistics, and are
stable under a large magnetic field. These results suggest that the low
temperature state is a glassy electronic state. Resistance relaxation and
memory effects of pure magnetic origin are also observed, but without aging
phenomena. This indicates that these magnetic effects are not glassy-like and
are not directly coupled to the electronic part.Comment: accepted in Phys Rev B, Brief report
Homogeneous Open Quantum Random Walks on a lattice
We study Open Quantum Random Walks for which the underlying graph is a
lattice, and the generators of the walk are translation-invariant. We consider
the quantum trajectory associated with the OQRW, which is described by a
position process and a state process. We obtain a central limit theorem and a
large deviation principle for the position process, and an ergodic result for
the state process. We study in detail the case of homogeneous OQRWs on a
lattice, with internal space
Thickness and angular dependent magnetic anisotropy of La0.67Sr0.33MnO3 thin films by Vectorial Magneto Optical Kerr Magnetometry
Magnetic states and spin-glass properties in Bi0.67Ca0.33MnO3: macroscopic ac measurements and neutron scattering
We report on the magnetic properties of the manganite Bi_{1-x}Ca_{x}MnO_3
(x=0.33) at low temperature. The analysis of the field expansion of the ac
susceptibility and the observation of aging properties make clear that a spin
glass phase appears below T = 39K, in the presence of magnetic order. Neutron
scattering shows both magnetic Bragg scattering and magnetic diffusion at small
angles, and confirms this coexistence. In contrast to Pr_{1-x}Ca_{x}MnO_3
(x=0.3-0.33) which exhibits a mesoscopic phase separation responsible for a
field driven percolation, the glassy and short range ferromagnetic order
observed here does not cause colossal magnetoresistance (CMR).Comment: accepted in Phys Rev
Evidence for LineLike Vortex Liquid Phase in TlBaCaCuO Probed by the Josephson Plasma Resonance
We measured the Josephson plasma resonance (JPR) in optimally doped
TlBaCaCuO thin films using terahertz time-domain
spectroscopy in transmission. The temperature and magnetic field dependence of
the JPR frequency shows that the c-axis correlations of pancake vortices remain
intact at the transition from the vortex solid to the liquid phase. In this
respect TlBaCaCuO films, withanisotropy parameter
, are similar to the less anisotropic
YBaCuO rather than to the most
anisotropic BiSrCaCuO single crystals ).Comment: Submitted to Physical Review Letter
Room temperature biaxial magnetic anisotropy in La0.67Sr0.33MnO3 thin films on SrTiO3 buffered MgO (001) substrates for spintronic applications
Identification of the amino-acetonitrile derivative monepantel (AAD 1566) as a new anthelmintic drug development candidate
Anthelmintic resistance has become a global phenomenon in gastro-intestinal nematodes of farm animals, including multi-drug resistance against the three major classes of anthelmintics. There is an urgent need for an anthelmintic with a new mode of action. The recently discovered amino-acetonitrile derivatives (AADs) offer a new class of synthetic chemicals with anthelmintic activity. The evaluation of AADs was pursued applying in vitro assays and efficacy and tolerability studies in rodents, sheep, and cattle. Amongst various suitable compounds, AAD 1566 eliminated many tested pathogenic nematode species, both at larval and adult stages, at a dose of 2.5Â mg/kg bodyweight in sheep and 5.0Â mg/kg bodyweight in cattle. The same doses were sufficient to cure animals infected with resistant or multi-drug-resistant nematode isolates. These findings, complemented by the good tolerability and low toxicity to mammals, suggest that AAD 1566, monepantel, would be a suitable anthelmintic drug development candidate
Using an on-line image analysis technique to characterize sucrose crystal morphology during a crystallization run
The morphological forms and habits of crystals and agglomeration are important properties on crystallization
processes. Online techniques for realtime measurement of these properties are mandatory for a better comprehension of crystal
growth phenomenon. The present paper presents and describes a new online method to determine the complexity level of a crystal
or a population of crystals during a crystallization process. An image analysis technique is combined with discriminant factorial
analysis leading to results that allow the computation of the complexity of crystals through the parameter agglomeration degree of
crystals. With this methodology, it has been possible to distinguish online and automatically among three different classes of crystals
according to their complexity. It further describes the application of such methodology on the study of CaCl2, D-fructose, and
D-glucose influence on the crystallization of sucrose, namely, on crystal size, morphology, and complexity. The effect of
supersaturation, growth rate, and impurity concentration on the type, amount, and complexity level of the agglomerates was
determined at different temperatures. The combination of image analysis and kinetic results allowed to understand better the
crystallization phenomena in the presence and absence of impurities. The image analysis results suggest the possible application of
this tool for process control, optimizing, by this way, laboratory and industrial crystallizers.This work was supported by Fundacao para a Ciencia e Tecnologia under program contract numbers SFRH/BD/11315/2002 and SFRH/BPD/45637/2008
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