2,926 research outputs found

    An ultra-compact low temperature scanning probe microscope for magnetic fields above 30 T

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    We present the design of a highly compact High Field Scanning Probe Microscope (HF-SPM) for operation at cryogenic temperatures in an extremely high magnetic field, provided by a water-cooled Bitter magnet able to reach 38 T. The HF-SPM is 14 mm in diameter: an Attocube nano-positioner controls the coarse approach of a piezo resistive AFM cantilever to a scanned sample. The Bitter magnet constitutes an extreme environment for SPM due to the high level of vibrational noise; the Bitter magnet noise at frequencies up to 300 kHz is characterized and noise mitigation methods are described. The performance of the HF-SPM is demonstrated by topographic imaging and noise measurements at up to 30 T. Additionally, the use of the SPM as a three-dimensional dilatometer for magnetostriction measurements is demonstrated via measurements on a magnetically frustrated spinel sample.Comment: 6 pages, 5 figure

    Sensing Noncollinear Magnetism at the Atomic Scale Combining Magnetic Exchange and Spin-Polarized Imaging

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    Storing and accessing information in atomic-scale magnets requires magnetic imaging techniques with single-atom resolution. Here, we show simultaneous detection of the spin-polarization and exchange force, with or without the flow of current, with a new method, which combines scanning tunneling microscopy and non-contact atomic force microscopy. To demonstrate the application of this new method, we characterize the prototypical nano-skyrmion lattice formed on a monolayer of Fe/Ir(111). We resolve the square magnetic lattice by employing magnetic exchange force microscopy, demonstrating its applicability to non-collinear magnetic structures, for the first time. Utilizing distance-dependent force and current spectroscopy, we quantify the exchange forces in comparison to the spin-polarization. For strongly spin-polarized tips, we distinguish different signs of the exchange force which we suggest arises from a change in exchange mechanisms between the probe and a skyrmion. This new approach may enable both non-perturbative readout combined with writing by current-driven reversal of atomic-scale magnets

    The Global Structure and Evolution of a Self-Gravitating Multi-phase Interstellar Medium in a Galactic Disk

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    Using high resolution, two-dimensional hydrodynamical simulations, we investigate the evolution of a self-gravitating multi-phase interstellar medium in the central kiloparsec region of a galactic disk. We find that a gravitationally and thermally unstable disk evolves, in a self-stabilizing manner, into a globally quasi-stable disk that consists of cold (T < 100 K), dense clumps and filaments surrounded by hot (T > 10^4 K), diffuse medium. The quasi-stationary, filamentary structure of the cold gas is remarkable. The hot gas, characterized by low-density holes and voids, is produced by shock heating. The shocks derive their energy from differential rotation and gravitational perturbations due to the formation of cold dense clumps. In the quasi-stable phase where cold and dense clouds are formed, the effective stability parameter, Q, has a value in the range 2-5. The dynamic range of our multi-phase calculations is 10^6 - 10^7 in both density and temperature. Phase diagrams for this turbulent medium are analyzed and discussed.Comment: 10 pages, 3 figures, ApJ Letters in press (vol. 516

    Breaking boundaries for biodiversity : expanding the policy agenda to halt biodiversity loss

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    Our assessment from the perspective of the Netherlands, a country in the temperate zone, showed a slightly positive picture, in line with the overall results for this zone. The loss of biodiversity in the Netherlands has been slowed down, but the European target – halting the loss of biodiversity – could not be met. The picture in the Netherlands is less positive if the average low quality of the remaining Dutch biodiversity is taken into account. If the impacts on biodiversity abroad of imports into the Netherlands are also included, we conclude that the Netherlands is not succeeding in slowing down the loss of biodiversity

    The cheeseboard in Dutch fine dining restaurants, II: Integration of the cheese course into the menu

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    In Dutch fine dining restaurants, the customer who orders a cheeseboard as part of the dessert is served an assortment of cheeses without regard to the dishes that preceded the cheese. The present paper tries to contribute to a more logical order of main dish and cheeseboard. A panel of 12 tasters judged the order of 6 cheeses with three dishes: vegetarian, beef, fish. The most appreciated cheeses were different for each dish. A good match in flavour profile between the dish and the best follow-up cheese was found.Keywords: Fine dining restaurants, menu structure, flavour profiles, flavour style
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