202 research outputs found
Exchange bias and interface electronic structure in Ni/Co3O4(011)
A detailed study of the exchange bias effect and the interfacial electronic
structure in Ni/Co3O4(011) is reported. Large exchange anisotropies are
observed at low temperatures, and the exchange bias effect persists to
temperatures well above the Neel temperature of bulk Co3O4, of about 40 K: to
~80 K for Ni films deposited on well ordered oxide surfaces, and ~150 K for Ni
films deposited on rougher Co3O4 surfaces. Photoelectron spectroscopy
measurements as a function of Ni thickness show that Co reduction and Ni
oxidation occur over an extended interfacial region. We conclude that the
exchange bias observed in Ni/Co3O4, and in similar ferromagnetic metallic/Co3O4
systems, is not intrinsic to Co3O4 but rather due to the formation of CoO at
the interface.Comment: 8 pages, 6 figures. Accepted for publication in Physical Review B
Validating a generic cancer consumer quality index in eight European countries, patient reported experiences and the influence of cultural differences
BackgroundTaking patient centeredness into account is important in healthcare. The European Cancer Consumer Quality Index (ECCQI) is a validated tool for international benchmarking of patient experiences and satisfaction.This study aimed to further validate the ECCQI in larger and more uniform groups of high volume tumours such as breast and prostate cancer. A second objective was the verification of the influence of cultural factors of the country to determine its possible use in international benchmarking.MethodsData from two survey studies in eight European countries were combined. Socio-demographic correlations were analysed with Kruskall-Wallis and Mann-Whitney tests. Cronbach's alpha was calculated to validate internal consistency. Influences of masculinity (MAS), power distance (PD) and uncertainty avoidance (UA) were determined by linear regression analysis in a general model and subgroup models.ResultsA total of 1322 surveys were included in the analysis (1093 breast- and 348 prostate cancer patients). Cronbach's alpha was good (alpha >= 0.7) or acceptable (0.5Peer reviewe
Spectral dependence of photoinduced spin precession in DyFeO3
Spin precession was nonthermally induced by an ultrashort laser pulse in
orthoferrite DyFeO3 with a pump-probe technique. Both circularly and linearly
polarized pulses led to spin precessions; these phenomena are interpreted as
the inverse Faraday effect and the inverse Cotton-Mouton effect, respectively.
For both cases, the same mode of spin precession was excited; the precession
frequencies and polarization were the same, but the phases of oscillations were
different. We have shown theoretically and experimentally that the analysis of
phases can distinguish between these two mechanisms. We have demonstrated
experimentally that in the visible region, the inverse Faraday effect was
dominant, whereas the inverse Cotton-Mouton effect became relatively prominent
in the near-infrared region.Comment: 27 pages, 8 figure
Tracking magnetic bright point motions through the solar atmosphere
High-cadence, multiwavelength observations and simulations are employed for the analysis of solar photospheric magnetic bright points (MBPs) in the quiet Sun. The observations were obtained with the Rapid Oscillations in the Solar Atmosphere (ROSA) imager and the Interferometric Bidimensional Spectrometer at the Dunn Solar Telescope. Our analysis reveals that photospheric MBPs have an average transverse velocity of approximately 1 km s−1, whereas their chromospheric counterparts have a slightly higher average velocity of 1.4 km s−1. Additionally, chromospheric MBPs were found to be around 63 per cent larger than the equivalent photospheric MBPs. These velocity values were compared with the output of numerical simulations generated using the MURAM code. The simulated results were similar, but slightly elevated, when compared to the observed data. An average velocity of 1.3 km s−1 was found in the simulated G-band images and an average of 1.8 km s−1 seen in the velocity domain at a height of 500 km above the continuum formation layer. Delays in the change of velocities were also analysed. Average delays of ∼4 s between layers of the simulated data set were established and values of ∼29 s observed between G-band and Ca II K ROSA observations. The delays in the simulations are likely to be the result of oblique granular shock waves, whereas those found in the observations are possibly the result of a semi-rigid flux tube
Space efficient opposed-anvil high-pressure cell and its application to optical and NMR measurements up to 9 GPa
We have developed a new type of opposed-anvil high pressure cell with
substantially improved space efficiency. The clamp cell and the gasket are made
of non-magnetic Ni-Cr-Al alloy. Non-magnetic tungsten carbide (NMWC) is used
for the anvils. The assembled cell with the dimension \phi 29mm \times 41mm is
capable of generating pressure up to 9 GPa over a relatively large volume of 7
mm3. Our cell is particularly suitable for those experiments which require
large sample space to achieve good signal-to-noise ratio, such as the nuclear
magnetic resonance (NMR) experiment. Argon is used as the pressure transmitting
medium to obtain good hydrostaticity. The pressure was calibrated in situ by
measuring the fluorescence from ruby through a transparent moissanite (6H-SiC)
window. We have measured the pressure and temperature dependences of the 63Cu
nuclear-quadrupole-resonance (NQR) frequency of Cu2O, the in-plane Knight shift
of metallic tin, and the Knight shift of platinum. These quantities can be used
as reliable manometers to determine the pressure values in situ during the
NMR/NQR experiments up to 9 GPa.Comment: 9 pages, 5 figures, 3 tables, accepted for publication in J. Phys.
Soc. Jp
DKIST unveils the serpentine topology of quiet Sun magnetism in the photosphere
We present the first quiet Sun spectropolarimetric observations obtained with
the Visible SpectroPolarimeter (ViSP) at the m Daniel K. Inouye Solar
Telescope (DKIST). We recorded observations in a wavelength range that includes
the magnetically sensitive Fe I doublet. With an
estimated spatial resolution of 0.08'', this represents the highest spatial
resolution full-vector spectropolarimetric observations ever obtained of the
quiet Sun. We identified small-scale magnetic elements, including
magnetic loops and unipolar magnetic patches, with linear and circular
polarisation detected in all of them. Of particular interest is a magnetic
element in which the polarity of the magnetic vector appears to change three
times in only km and which has linear polarisation signals throughout. We
find complex Stokes profiles at the polarity inversion lines of magnetic
loops and discover degenerate solutions, as we are unable to conclusively
determine whether these arise due to gradients in the atmospheric parameters or
smearing of opposite polarity signals. We analyse a granule which notably has
linear and circular polarisation signals throughout, providing an opportunity
to explore its magnetic properties. On this small scale we see the magnetic
field strength range from G at the granular boundary to kG in the
intergranular lane (IGL), and sanity check the values with the weak and strong
field approximations. A value of kG in the IGL is among the highest
measurements ever recorded for the internetwork.Comment: Accepted for publication in ApJ
Magnetic properties of X-Pt (X=Fe,Co,Ni) alloy systems
We have studied the electronic and magnetic properties of Fe-Pt, Co-Pt and
Ni-Pt alloy systems in ordered and disordered phases. The influence of various
exchange-correlation functionals on values of equilibrium lattice parameters
and magnetic moments in ordered Fe-Pt, Co-Pt and Ni-Pt alloys have been studied
using linearized muffin-tin orbital method. The electronic structure
calculations for the disordered alloys have been carried out using augmented
space recursion technique in the framework of tight binding linearized
muffin-tin orbital method. The effect of short range order has also been
studied in the disordered phase of these systems. The results show good
agreements with available experimental values.Comment: 21 pages, 4 eps figures, accepted for publication in Journal of
Physics Condensed Matte
Observed Effect of Magnetic Fields on the Propagation of Magnetoacoustic Waves in the Lower Solar Atmosphere
We study Hinode/SOT-FG observations of intensity fluctuations in Ca II H-line
and G-band image sequences and their relation to simultaneous and co-spatial
magnetic field measurements. We explore the G-band and H-line intensity
oscillation spectra both separately and comparatively via their relative phase
differences, time delays and cross-coherences. In the non-magnetic situations,
both sets of fluctuations show strong oscillatory power in the 3 - 7 mHz band
centered at 4.5 mHz, but this is suppressed as magnetic field increases. A
relative phase analysis gives a time delay of H-line after G-band of 20\pm1 s
in non-magnetic situations implying a mean effective height difference of 140
km. The maximum coherence is at 4 - 7 mHz. Under strong magnetic influence the
measured delay time shrinks to 11 s with the peak coherence near 4 mHz. A
second coherence maximum appears between 7.5 - 10 mHz. Investigation of the
locations of this doubled-frequency coherence locates it in diffuse rings
outside photospheric magnetic structures. Some possible interpretations of
these results are offered.Comment: 19 pages, 6 figure
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