3,037 research outputs found
Stoner gap in the superconducting ferromagnet UGe2
We report the temperature () dependence of ferromagnetic Bragg peak
intensities and dc magnetization of the superconducting ferromagnet UGe2 under
pressure (). We have found that the low- behavior of the uniform
magnetization can be explained by a conventional Stoner model. A functional
analysis of the data produces the following results: The ferromagnetic state
below a critical pressure can be understood as the perfectly polarized state,
in which heavy quasiparticles occupy only majority spin bands. A Stoner gap
decreases monotonically with increasing pressure and increases
linearly with magnetic field. We show that the present analysis based on the
Stoner model is justified by a consistency check, i.e., comparison of density
of states at the Fermi energy deduced from the analysis with observed
electronic specific heat coeffieients. We also argue the influence of the
ferromagnetism on the superconductivity.Comment: 5 pages, 4 figures. to be published in Phys. Rev.
Vaginal yeasts in the era of "over the counter" antifungals
OBJECTIVE: To establish whether there has been any rise in the prevalence of non-albicans
Candida species isolated from vaginal swabs since the introduction of “over the counter” antifungal
treatments.
METHOD: A retrospective review looking at all positive vaginal yeast isolates collected from
women attending one genitourinary medicine clinic during the 6 year period from 1993 to 1998
inclusive. All positive vaginal yeast isolates were included, regardless of whether or not the
patients were symptomatic. Isolates from HIV positive women were excluded from the analysis.
RESULT: No increase in non-albicans vaginal yeast isolates was shown during the period studied.
The proportion of non-albicans yeasts remained constant at approximately 5% of the total yeasts
isolated. The most common non-albicans yeast isolated was C glabrata.
CONCLUSION: There is no evidence from this study to suggest that the increasing use of “over the
counter” antifungal treatment has selected for atypical, possibly inherently azole resistant, strains
of vaginal yeasts in HIV seronegative women
Anomalous phase of MnP at very low field
Manganese phosphide MnP has been investigated for decades because of its rich
magnetic phase diagram. It is well known that the MnP exhibits the
ferromagnetic phase transition at \Tc=292 K and the helical magnetic phase
below \TN=47 K at zero field. Recently, a novel magnetic phase transition was
observed at K when the magnetic field is lower than 5 Oe. However,
the nature of the new phase has not been illuminated yet. In order to reveal
it, we performed the AC and the DC magnetization measurements for a single
crystal MnP at very low field. A divergent behavior of the real and the
imaginary part of the AC susceptibility and a sharp increase of the DC
magnetization was observed at , indicating the magnetic phase transition
at . Furthermore a peculiar temperature hysteresis was observed: namely,
the magnetization depends on whether cooling sample to the temperature lower
than \TN or not before the measurements. This hysteresis phenomenon suggests
the complicated nature of the new phase and a strong relation between the
magnetic state of the new phase and the helical structure.Comment: 4 pages, 2 figure
Magnetic structure, phase diagram, and a new type of spin-flop transition dominated by higher order interaction in a localized 5f system U3Pd20Si6
The magnetic structure of the localized-5f uranium intermetallic compound U3Pd20Si6 has been determined by means of a neutron diffraction experiment. Our data demonstrate that this compound has a collinear coupling of the sublattice ordering of the uranium spins on the 4a and 8c sites. We conclude that higher-order exchange and/or quadrupole interactions are necessary to stabilize this unique collinear structure. We discovered a new type of spin-flop transition against the uniaxial anisotropy induced by this collinear coupling
No Keplerian Disk >10 AU around the Protostar B335: Magnetic Braking or Young Age?
We have conducted ALMA cycle 2 observations in the 1.3 mm continuum and in
the C18O (2-1) and SO (5_6-4_5) lines at a resolution of ~0.3" toward the Class
0 protostar B335. The 1.3 mm continuum, C18O, and SO emission all show central
compact components with sizes of ~40-180 AU within more extended components.
The C18O component shows signs of infalling and rotational motion. By fitting
simple kinematic models to the C18O data, the protostellar mass is estimated to
be 0.05 Msun. The specific angular momentum, on a 100 AU scale, is ~4.3E-5
km/s*pc. A similar specific angular momentum, ~3E-5 to 5E-5 km/s*pc, is
measured on a 10 AU scale from the velocity gradient observed in the central SO
component, and there is no clear sign of an infalling motion in the SO
emission. By comparing the infalling and rotational motion, our ALMA results
suggest that the observed rotational motion has not yet reached Keplerian
velocity neither on a 100 AU nor even on a 10 AU scale. Consequently, the
radius of the Keplerian disk in B335 (if present) is expected to be 1-3 AU. The
expected disk radius in B335 is one to two orders of magnitude smaller than
those of observed Keplerian disks around other Class 0 protostars. Based on the
observed infalling and rotational motion from 0.1 pc to inner 100 AU scales,
there are two possible scenarios to explain the presence of such a small
Keplerian disk in B335: magnetic braking and young age. If our finding is the
consequence of magnetic braking, ~50% of the angular momentum of the infalling
material within a 1000 AU scale might have been removed, and the magnetic field
strength on a 1000 AU scale is estimated to be ~200 uG. If it is young age, the
infalling radius in B335 is estimated to be ~2700 AU, corresponding to a
collapsing time scale of ~5E4 yr.Comment: Accepted by Ap
Observation of Modulated Quadrupolar Structures in PrPb3
Neutron diffraction measurements have been performed on the cubic compound
PrPb3 in a [001] magnetic field to examine the quadrupolar ordering.
Antiferromagnetic components with q=(1/2+-d 1/2 0), (1/2 1/2+-d 0) (d~1/8) are
observed below the transition temperature TQ (0.4 K at H=0) whose amplitudes
vary linear with H and vanish at zero field, providing the first evidence for a
modulated quadrupolar phase. For H<1 T, a non-square modulated state persists
even below 100 mK suggesting quadrupole moments associated with a Gamma3
doublet ground state to be partially quenched by hybridization with conduction
electrons.Comment: Physical Review Letters, in press. 4 pages, 4 figure
Stabilization of a Fabry-Perot interferometer using a suspension-point interferometer
A suspension-point interferometer (SPI) is an auxiliary interferometer for
active vibration isolation, implemented at the suspension points of the mirrors
of an interferometric gravitational wave detector. We constructed a prototype
Fabry-Perot interferometer equipped with an SPI and observed vibration
isolation in both the spectrum and transfer function. The noise spectrum of the
main interferometer was reduced by 40 dB below 1 Hz. Transfer function
measurements showed that the SPI also produced good vibration suppression above
1 Hz. These results indicate that SPI can improve both the sensitivity and the
stability of the interferometer.Comment: 14 pages, 8 figures; added discussion; to be published in Physics
Letters
The Phonology of Landawe Language
This study aims at investigating the phonology of Landawe Language. The data collecting was done by participant speaking and scrutinizing methods. It was analyzed using apportioned methods. Landawe language has 10 vowel sounds, but there are only five sounds proved as vowel phonemes, they are /i, a, e, o, u/. Besides, Landawe language has 18consonant sounds, they are:/b/, /p/, /d/, /t/, /g/, /k/, /ŋ/, /m/, /n/, /s/, /h/, /l/, /r/, /c/ /y/, /j/, /w/, and /ʔ/. Those consonant sounds are proved as the phoneme. Based on the distribution of the consonant, there is not any consonant that places the final position. They just place the initial and the medial of the word, except /ʔ/ and /y/that only place the medial position, and /j/ that only place the initial position. It means that Landawe language is categorized as vocalist language
Local Moment Formation in the Periodic Anderson Model with Superconducting Correlations
We study local moment formation in the presence of superconducting
correlations among the f-electrons in the periodic Anderson model. Local
moments form if the Coulomb interaction U>U_cr. We find that U_cr is
considerably stronger in the presence of superconducting correlations than in
the non-superconducting system. Our study is done for various values of the
f-level energy and electronic density. The smallest critical U_cr values occur
for the case where the number of f- electrons per site is equal to one. In the
presence of d-wave superconducting correlations we find that local moment
formation presents a quantum phase transition as function of pressure. This
quantum phase transition separates a region where local moments and d-wave
superconductivity coexist from another region characterized by a
superconducting ground state with no local moments. We discuss the possible
relevance of these results to experimental studies of the competition between
magnetic order and superconductivity in CeCu_2Si_2.Comment: 4 pages. accepted for publication in Phys. Rev.
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