24 research outputs found
Josephson Plasma in RuSr2GdCu2O8
Josephson plasma in RuSrGdCuO,
RuSrGdCuO (x = 0.3), and
RuSrEuCeCuO (x = 0.5) compounds is
investigated by the sphere resonance method. The Josephson plasma is observed
in a low-frequency region (around 8.5 cm at T ) for
ferromagnetic RuSrGdCuO, while it increases to 35 cm
for non-ferromagnetic RuSrGdCuO (x = 0.3), which
represents a large reduction in the Josephson coupling at ferromagnetic
RuO block layers. The temperature dependence of the plasma does not shift
to zero frequency ({\it i.e.} = 0) at low temperatures, indicating that
there is no transition from the 0-phase to the -phase in these compounds.
The temperature dependence and the oscillator strength of the peak are
different from those of other non-magnetic cuprates, and the origins of these
anomalies are discussed.Comment: to appear in Phys. Rev.B Rapid Com
Melting of Charge/Orbital Ordered States in NdSrMnO: Temperature and Magnetic Field Dependent Optical Studies
We investigated the temperature ( 15 290 K) and the magnetic
field ( 0 17 T) dependent optical conductivity spectra of a
charge/orbital ordered manganite, NdSrMnO. With variation
of and , large spectral weight changes were observed up to 4.0 eV. These
spectral weight changes could be explained using the polaron picture.
Interestingly, our results suggested that some local ordered state might remain
above the charge ordering temperature, and that the charge/orbital melted state
at a high magnetic field (i.e. at 17 T and 4.2 K) should be a three
dimensional ferromagnetic metal. We also investigated the first order phase
transition from the charge/orbital ordered state to ferromagnetic metallic
state using the - and % -dependent dielectric constants . In
the charge/orbital ordered insulating state, was positive and
. With increasing and , was
increased up to the insulator-metal phase boundaries. And then,
abruptly changed into negative and , which was
consistent with typical responses of a metal. Through the analysis of using an effective medium approximation, we found that the melting
of charge/orbital ordered states should occur through the percolation of
ferromagnetic metal domains.Comment: submitted to Phys. Rev.
Optical Investigations of Charge Gap in Orbital Ordered La1/2Sr3/2MnO4
Temperature and polarization dependent electronic structure of La1/2Sr3/2MnO4
were investigated by optical conductivity analyses. With decreasing
temperature, for E//ab, a broad mid-infrared (MIR) peak of La1/2Sr3/2MnO4
becomes narrower and moves to the higher frequency, while that of
Nd1/2Sr3/2MnO4 nearly temperature independent. We showed that the MIR peak in
La1/2Sr3/2MnO4 originates from orbital ordering associated with CE-type
magnetic ordering and that the Jahn-Teller distortion has a significant
influence on the width and the position of the MIR peak.Comment: 10 pages, 4 figure
Current Distribution in the Three-Dimensional Random Resistor Network at the Percolation Threshold
We study the multifractal properties of the current distribution of the
three-dimensional random resistor network at the percolation threshold. For
lattices ranging in size from to we measure the second, fourth and
sixth moments of the current distribution, finding {\it e.g.\/} that
where is the conductivity exponent and is the
correlation length exponent.Comment: 10 pages, latex, 8 figures in separate uuencoded fil
Optical Evidence of Multiphase Coexistence in Single Crystalline (La,Pr,Ca)MnO3
We investigated temperature (T)- and magnetic field-dependent optical
conductivity spectra (\s\w) of a La_5/8-yPr_yCa_3/8MnO_3 (y~0.35) single
crystal, showing intriguing phase coexistence at low T. At T_C < T < T_CO, a
dominant charge-ordered phase produces a large optical gap energy of ~0.4 eV.
At T < T_C, at least two absorption bands newly emerge below 0.4 eV. Analyses
of (\s\w) indicate that the new bands should be attributed to a ferromagnetic
metallic and a charge-disordered phase that coexist with the charge-ordered
phase. This optical study clearly shows that La_5/8-yPrCa_3/8MnO_3 (y~0.35) is
composed of multiphases that might have different lattice strains.Comment: A single file with 9 figures embedded, to appear in Phys. Rev.
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362