1,860 research outputs found
Isotope effect on the transition temperature in Fe-based superconductors: the current status
The results of the Fe isotope effect (Fe-IE) on the transition temperature
obtained up to date in various Fe-based high temperature superconductors
are summarized and reanalyzed by following the approach developed in [Phys.
Rev. B 82, 212505 (2010)]. It is demonstrated that the very controversial
results for Fe-IE on are caused by small structural changes occurring
simultaneously with the Fe isotope exchange. The Fe-IE exponent on
[, is the isotope mass]
needs to be decomposed into two components with the one related to the
structural changes () and the genuine (intrinsic)
one (). The validity of such decomposition is
further confirmed by the fact that coincides with
the Fe-IE exponent on the characteristic phonon frequencies as is reported in recent EXAFS and Raman experiments.Comment: 7 pages, 4 figures. The paper is partially based on the results
published in [New J. Phys. 12, 073024 (2010) = arXiv:1002.2510] and [Phys.
Rev. B 82, 212505 (2010) = arXiv:1008.4540
Manifestation of vortex depinning transition in nonlinear current-voltage characteristics of polycrystalline superconductor Y_{1-x}Pr_{x}Ba_2Cu_3O_7
We present our recent results on the temperature dependence of
current-voltage characteristics for polycrystalline Y_{1-x}Pr_{x}Ba_2Cu_3O_7
superconductors with x = 0.0, 0.1 and 0.3. The experimental results are found
to be reasonably well fitted for all samples by a power like law. According to
the theoretical interpretation of the obtained results, nonlinear deviation of
our current-voltage characteristics curves from Ohmic behavior below Tc is
attributed to the manifestation of dissipation processes related to the current
induced depinning of Abrikosov vortices.Comment: Accepted for publication in PL
Perspective on the muon-spin rotation/relaxation under hydrostatic pressure
Pressure, together with temperature, electric and magnetic fields, alters the
system and allows to investigate the fundamental properties of the matter.
Under applied pressure the interatomic distances shrink, which modify
interactions between atoms and may lead to appearance of a new (sometime
exotic) physical properties as, e.g., pressure induced phase transition(s);
quantum critical points(s), new structural, magnetic and/or superconducting
states; changes of the temperature evolution and the symmetry of the order
parameter(s) etc. The muon-spin rotation/relaxation (SR) appears to be a
commonly used powerful technique allowing to study the magnetic and
superconducting responses of various materials under extreme conditions. At
present, SR experiments might be performed under the high magnetic field
up to T, temperatures down to mK and hydrostatic
pressure up to GPa. In the following Perspective paper the
requirements to the SR under pressure experiments, the existing
high-pressure muon facility at the Paul Scherrer Institute (Switzerland), and
selected experimental results obtained by using the SR under pressure
technique are discussed.Comment: 14 pages, 14 figure
VALEOLOGICAL ASPECTS OF HEALTHY LIFESTYLE OF YOUNG GENERATION
This article analyses knowledge of students in the process of testing of students Urgench State University, while learning Valeology and Physical training subject
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