570 research outputs found

    Quantum criticality near the upper critical field of Ce2_2PdIn8_8

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    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 Ce2_2PdIn8_8. In contrast to its quasi-two-dimensional (2D) relative CeCoIn5_5, the system displays an almost isotropic upper critical field. While there is no indication for a FFLO phase in Ce2_2PdIn8_8, the data suggest a smeared weak first-order superconducting transition close to Hc22H_{c2}\approx 2 T. The normal state electronic specific heat coefficient displays logarithmically divergent behavior, comparable to CeCoIn5_5 and in agreement with 2D quantum criticality of spin-density-wave type

    Search for quantum criticality in a ferromagnetic system UNi1-xCoxSi2

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    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

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    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

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    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.

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    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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