1,779 research outputs found
P-Star-Model Based Analysis of Inflation Dynamic in the Czech Republic.
The paper presents a version of the P* model of inflation dynamics for a small open economy and applies it to the Czech economy time series from the period of 1991-1999. The paper is organized as follows. Section 2 presents a brief discussion of the monetary policy indicators issue. Section 3 describes the logics of the P* model. Section 4 explains the extension of the basic model to the case of a small open economy. Section 5 applies the model to the Czech economy data and presents the estimates of the Czech inflation dynamics determination.INFLATION ; TIME SERIES ; MONETARY POLICY
Multiferroicity in the frustrated spinel cuprate GeCuO
Different from other magnetically frustrated spinel systems,
GeCuO is a strongly tetragonal distorted spinel cuprate in which
edge-sharing CuO ribbons are running along alternating directions
perpendicular to the -axis. Here, GeCuO samples of high quality
were prepared via high pressure synthesis (at 4 GPa) and the corresponding
magnetic and dielectric properties were investigated. For the first time, we
observed a ferroelectric polarization emerging at T 33~K. Although
the ferroelectric polarization is weak in GeCuO (
0.2C/m), the existence of spin-induced multiferroicity provides a
strong constraint on the possible ground state magnetic structures and/or the
corresponding theoretical models of multiferroicity for GeCuO.Comment: https://journals.aps.org/prmaterials/abstract/10.1103/PhysRevMaterials.2.04140
The One Quail Per Acre Myth
Data are presented which conflict with the 1-bird-per-acre saturation point concept for bobwhites (Colinus virginianus). Conclusions are that if a saturation point exists it is at a level greater than 2 bobwhites per acre
Magnetically induced Ferroelectricity in BiCuO
The tetragonal copper oxide BiCuO has an unusual crystal structure
with a three-dimensional network of well separated CuO plaquettes. This
material was recently predicted to host electronic excitations with an
unconventional spectrum and the spin structure of its magnetically ordered
state appearing at T 43 K remains controversial. Here we present the
results of detailed studies of specific heat, magnetic and dielectric
properties of BiCuO single crystals grown by the floating zone
technique, combined with the polarized neutron scattering and high-resolution
X-ray measurements. Our polarized neutron scattering data show Cu spins are
parallel to the plane. Below the onset of the long range antiferromagnetic
ordering we observe an electric polarization induced by an applied magnetic
field, which indicates inversion symmetry breaking by the ordered state of Cu
spins. For the magnetic field applied perpendicular to the tetragonal axis, the
spin-induced ferroelectricity is explained in terms of the linear
magnetoelectric effect that occurs in a metastable magnetic state. A relatively
small electric polarization induced by the field parallel to the tetragonal
axis may indicate a more complex magnetic ordering in BiCuO
Verwey transition in FeO thin films: Influence of oxygen stoichiometry and substrate-induced microstructure
We have carried out a systematic experimental investigation to address the
question why thin films of FeO (magnetite) generally have a very broad
Verwey transition with lower transition temperatures as compared to the bulk.
We observed using x-ray photoelectron spectroscopy, x-ray diffraction and
resistivity measurements that the Verwey transition in thin films is
drastically influenced not only by the oxygen stoichiometry but especially also
by the substrate-induced microstructure. In particular, we found (1) that the
transition temperature, the resistivity jump, and the conductivity gap of fully
stoichiometric films greatly depends on the domain size, which increases
gradually with increasing film thickness, (2) that the broadness of the
transition scales with the width of the domain size distribution, and (3) that
the hysteresis width is affected strongly by the presence of antiphase
boundaries. Films grown on MgO (001) substrates showed the highest and sharpest
transitions, with a 200 nm film having a T of 122K, which is close to the
bulk value. Films grown on substrates with large lattice constant mismatch
revealed very broad transitions, and yet, all films show a transition with a
hysteresis behavior, indicating that the transition is still first order rather
than higher order.Comment: 9 pages, 12 figure
Penalized regression on principal manifolds with application to combustion modelling
For multivariate regression problems featuring strong and non–linear dependency patterns between the involved predictors, it is attractive to reduce the dimension of the estimation problem by approximating the predictor space through a principal surface (or manifold). In this work, a new approach for non- parametric regression onto the fitted manifold is provided. The proposed penal- ized regression technique is applied onto data from a simulated combustion sys- tem, and is shown, in this application, to compare well with competing regression routines
Intricacies of the Co spin state in SrCoIrO: an x-ray absorption and magnetic circular dichroism study
We report on a combined soft x-ray absorption and magnetic circular dichroism
(XMCD) study at the Co- on the hybrid 3/5 solid state oxide
SrCoIrO with the KNiF structure. Our data
indicate unambiguously a pure high spin state for the Co
(3) ions with a significant unquenched orbital moment
despite the sizeable elongation of the CoO octahedra. Using quantitative
model calculations based on parameters consistent with our spectra, we have
investigated the stability of this high spin state with respect to the
competing low spin and intermediate spin states.Comment: 7 pages, 4 figure
Gain and time resolution of 45 m thin Low Gain Avalanche Detectors before and after irradiation up to a fluence of n/cm
Low Gain Avalanche Detectors (LGADs) are silicon sensors with a built-in
charge multiplication layer providing a gain of typically 10 to 50. Due to the
combination of high signal-to-noise ratio and short rise time, thin LGADs
provide good time resolutions.
LGADs with an active thickness of about 45 m were produced at CNM
Barcelona. Their gains and time resolutions were studied in beam tests for two
different multiplication layer implantation doses, as well as before and after
irradiation with neutrons up to n/cm.
The gain showed the expected decrease at a fixed voltage for a lower initial
implantation dose, as well as for a higher fluence due to effective acceptor
removal in the multiplication layer. Time resolutions below 30 ps were obtained
at the highest applied voltages for both implantation doses before irradiation.
Also after an intermediate fluence of n/cm, similar
values were measured since a higher applicable reverse bias voltage could
recover most of the pre-irradiation gain. At n/cm, the
time resolution at the maximum applicable voltage of 620 V during the beam test
was measured to be 57 ps since the voltage stability was not good enough to
compensate for the gain layer loss. The time resolutions were found to follow
approximately a universal function of gain for all implantation doses and
fluences.Comment: 17 page
Electronic and magnetic nano phase separation in cobaltates LaSrCoO
The single-layer perovskite cobaltates have attracted enormous attention due
to the recent observation of hour-glass shaped magnetic excitation spectra
which resemble the ones of the famous high-temperature superconducting
cuprates. Here, we present an overview of our most recent studies of the spin
and charge correlations in floating-zone grown cobaltate single crystals. We
find that frustration and a novel kind of electronic and magnetic nano phase
separation are intimately connected to the appearance of the hour-glass shaped
spin excitation spectra. We also point out the difference between nano phase
separation and conventional phase separation.Comment: * plenary talk SUPERSTRIPES conference 201
Incommensurate spin correlations in highly oxidized cobaltates LaSrCoO
We observe quasi-static incommensurate magnetic peaks in neutron scattering
experiments on layered cobalt oxides La2-xSrxCoO4 with high Co oxidation states
that have been reported to be paramagnetic. This enables us to measure the
magnetic excitations in this highly hole-doped incommensurate regime and
compare our results with those found in the low-doped incommensurate regime
that exhibit hourglass magnetic spectra. The hourglass shape of magnetic
excitations completely disappears given a high Sr doping. Moreover, broad
low-energy excitations are found, which are not centered at the incommensurate
magnetic peak positions but around the quarter-integer values that are
typically exhibited by excitations in the checkerboard charge ordered phase.
Our findings suggest that the strong inter-site exchange interactions in the
undoped islands are critical for the emergence of hourglass spectra in the
incommensurate magnetic phases of La2-xSrxCoO4.Comment: http://www.nature.com/articles/srep25117
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