60 research outputs found
Cu(2) nuclear resonance evidence for an original magnetic phase in aged 60K-superconductors RBa2Cu3O6+x (R=Tm,Y)
It is widely believed that the long-range antiferromagnetic order in the
RBa2Cu3O6+x compounds (R=Y and rare earths except of Ce, Pr, Tb) is totally
suppressed for the oxygen index x>0.4 (AFM insulator-metal transition). We
present the results of the copper NQR/NMR studies of aged RBa2Cu3O6+x (R=Tm,Y)
samples showing that a magnetic order can still be present at oxygen contents x
up to at least 0.7 and at temperatures as high as 77K.Comment: 7 pages, 6 figures. Submitted to Phys.Rev.
Superconductivity in a Molecular Metal Cluster Compound
Compelling evidence for band-type conductivity and even bulk
superconductivity below K has been found in
Ga-NMR experiments in crystalline ordered, giant Ga
cluster-compounds. This material appears to represent the first realization of
a theoretical model proposed by Friedel in 1992 for superconductivity in
ordered arrays of weakly coupled, identical metal nanoparticles.Comment: 5 pages, 4 figure
Phase diagram of YBaCuO at TT based on Cu(2) transverse nuclear relaxation
Two maxima in transverse relaxation rate of Cu(2) nuclei in
YBaCuO are observed, at T = 35 K and T = 47 K. Comparison of
the Cu(2) and Cu(2) rates at T = 47 K indicates the magnetic
character of relaxation. The enhancement at T = 47 K of fluctuating local
magnetic fields perpendicular to the CuO planes is connected with the
critical fluctuations of orbital currents. Maximum at T = 35 K is connected
with the appearance of inhomogeneous supeconducting phase. Together with data
published to date, our experimental results allow to suggest a qualitatively
new phase diagram of the superconducting phase.Comment: 4 LaTEX pages + 3 figures in *.ps forma
Features Exterior of Cattle of Breed Limousian in the Period of Their Acclimation in the Conditions of the Northern Trans-Ural
The paper presents a characteristic of the exterior features of the specialized limousin meat breed bred in the conditions of the Tyumen region. Studies were conducted on first-calf cows of different generations of animals. At the same time, the introduced animals belong to the zero generation, their descendants to the 1st generation, and the grandchildren belong to the 2nd genetic-ecological generation. In the process of research, it was that the acclimatization process left its mark on the manifestation of the main breeding and productive qualities of the studied livestock generations. One of the manifestations of which was a certain grinding of cows of the first generation. The obtained results of the exterior assessment of cows of different generations showed that the best exterior development was observed in cows of the second and zero generation. So, in cows of the first and second generations there was a decrease in measurements of the chest, estimated by the chest index by 1.1â3.1 % (P> 0.999), with an increase in the proportions characterizing the development of meat qualities of animals by 6.2â6.6 % (P> 0.999). Adaptation to new conditions confirms the development of such indices as the typical physique and severity of type, which, when changing generations, had an increase dynamic
First time determination of the microscopic structure of a stripe phase: Low temperature NMR in La2NiO4.17
The experimental observations of stripes in superconducting cuprates and
insulating nickelates clearly show the modulation in charge and spin density.
However, these have proven to be rather insensitive to the harmonic structure
and (site or bond) ordering. Using 139La NMR in La2NiO4.17, we show that in the
1/3 hole doped nickelate below the freezing temperature the stripes are
strongly solitonic and site ordered with Ni3+ ions carrying S=1/2 in the domain
walls and Ni2+ ions with S=1 in the domains.Comment: 4 pages including 4 figure
Spin dynamics and ordering of a cuprate stripe-antiferromagnet
In La1.48Nd0.4Sr0.12CuO4 the 139La and 63Cu NQR relaxation rates and signal
wipe-out upon lowering temperature are shown to be due to purely magnetic
fluctuations. They follow the same renormalized classical behavior as seen in
neutron data, when the electronic spins order in stripes, with a small spread
in spin stiffness (15% spread in activation energy). The La signal, which
reappears at low temperatures, is magnetically broadened and experiences
additional wipe-out due to slowing down of the Nd fluctuations.Comment: 4 pages including 3 figures - ref. 16 adde
Effect of Autoclave Curing on the Microstructure of Blended Cement Mixture Incorporating Ground Dune Sand and Ground Granulated Blast Furnace Slag
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