570 research outputs found
Quantum criticality near the upper critical field of CePdIn
We report low-temperature specific heat measurements in magnetic fields up to
12 T applied parallel and perpendicular to the tetragonal c-axis of the heavy
fermion superconductor CePdIn. In contrast to its quasi-two-dimensional
(2D) relative CeCoIn, the system displays an almost isotropic upper
critical field. While there is no indication for a FFLO phase in
CePdIn, the data suggest a smeared weak first-order superconducting
transition close to T. The normal state electronic specific
heat coefficient displays logarithmically divergent behavior, comparable to
CeCoIn and in agreement with 2D quantum criticality of spin-density-wave
type
Search for quantum criticality in a ferromagnetic system UNi1-xCoxSi2
Polycrystalline samples of the isostructural alloys UNi1-xCoxSi2 (0 <= x <=
1) were studied by means of x-ray powder diffraction, magnetization, electrical
resistivity and specific heat measurements, at temperatures down to 2 K and in
magnetic fields up to 5 T. The experimental data revealed an evolution from
strongly anisotropic ferromagnetism with pronounced Kondo effect, observed for
the alloys with x < 0.98 and being gradually suppressed with rising Co-content,
to spin-glass-like states with dominant spin fluctuations, seen for the sample
with x = 0.98. Extrapolation of the value of TC(x) yields a critical
concentration xc = 1, at which the magnetic ordering entirely disappears. This
finding is in line with preliminary data collected for stoichiometric UCoSi2.Comment: to appear in Phys. Rev.
Magnetic and related properties of ternary TmTX intermetallics
We report on the magnetic and thermal properties of a few TmTX compounds, where T = d-electron metal and X = p-electron element. In all these ternaries but TmRuGe the thulium magnetic moments order antiferro- or ferromagnetically at low temperatures. The specific heat data confirms the magnetic orderings and reveals the influence of crystalline electric field effects
Breakdown of the de Gennes scaling in Y1-xDyxNi2B2C
Single crystals of Y1-xDyxΝi2B2C (1 ≤ x≤ 0.7) were examined by
X-ray diffraction and stoichiometry was attested by XPS measurements. The
superconducting transition temperature T^ and Neel temperature TN were
determined by means of magnetisation measurements. A dramatic breakdown
of the de Gennes scaling in the Dy-rich compounds was found when
< TN
Adaptive, spatially-varying aberration correction for real-time holographic projectors.
A method of generating an aberration- and distortion-free wide-angle holographically projected image in real time is presented. The target projector is first calibrated using an automated adaptive-optical mechanism. The calibration parameters are then fed into the hologram generation program, which applies a novel piece-wise aberration correction algorithm. The method is found to offer hologram generation times up to three orders of magnitude faster than the standard method. A projection of an aberration- and distortion-free image with a field of view of 90x45 degrees is demonstrated. The implementation on a mid-range GPU achieves high resolution at a frame rate up to 12fps. The presented methods are automated and can be performed on any holographic projector.Engineering and Physical Sciences Research CouncilThis is the final version of the article. It first appeared from the Optical Society of America via https://doi.org/10.1364/OE.24.01574
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