Interplay between Static and Dynamic Properties of Semifluxons in YBa2Cu3O7−δ 0−π Josephson Junctions

We have investigated the static and dynamic properties of long YBa2Cu3O7-delta 0-pi Josephson junctions and compared them with those of conventional 0 junctions. Scanning SQUID microscope imaging has revealed the presence of a semifluxon at the phase discontinuity point in 0-pi Josephson junctions. Zero field steps have been detected in the current-voltage characteristics of all junctions. Comparison with simulation allows us to attribute these steps to fluxons traveling in the junction for conventional 0 junctions and to fluxon-semifluxon interactions in the case of 0-pi Josephson junctions

A shock recovery experiment and its implications for Mercury's surface : The effect of high pressure on porous olivine powder as a regolith analog

We conducted classic dynamic high - pressure experiments on porous San Carlos (SC) olivine powder to examine if and how different shock stages modify corresponding reflectance mid – infrared (MIR) spectra. Microscopic investigation of the thin sections produced of our shocked samples indicates local peak pressures of >60 GPa along with all lower grade shock stages. Spectral analyses of optically identified shock areas were documented and compared in terms of Christiansen Feature (CF) and the position of olivine – diagnostic Reststrahlenbands (RBs). We found that one RB (fundamental vibrations of the orthosilicate - ion) of olivine occurring at 980 cm−1 (corresponding to ≈ 10.2 μm) shows the least energetic shift in the investigated MIR spectra and could therefore serve as a proxy for the presence of olivine in remote sensing application. Furthermore, a peak located at ≈ 1060 cm−1 (≈ 9.4 μm) shows a significant intensity change probably related to the degree of shock exposure or grain orientation effects, as we observe a decline in intensity of this band from our averaged reference olivine spectra of our IRIS database (diffuse reflectance measurement) down to spectra of grains showing mosaicism and recrystallized areas. We also report the presence of a weak band in some of the olivine spectra located at ≈ 1100 cm−1 (9.1 μm) that has an influence on the position of the CF when spectral data of olivine are averaged.Peer reviewe

Unmixing of Laboratory IR Spectral Reflectance Measurements of Smooth Plains Analogs

The unmixing model used in this study has previ- ously been used for spectral unmixing of NASA RELAB data and lunar analog materials. In the framework of MERTIS it is applied to laborator mineral mixtures, including glasses and varying grain sizes [12-14]. These mixtures are prepared and analyzed at the IRIS (Infrared and Raman for Interplanetary Spectros- copy) laboratory of the Institut für Planetologie at the Westfälische Wilhelms-Universität Münster. Here we investigate a wide range of natural minerals, rock samples including impact rocks and meteorites, syn- thetic analogs, and glasses [3,7]. The results of these in- vestigations contribute to the generation of a mid-IR re- flectance database in the MERTIS-relevant wavelength range from 7-14 μm. This database enables the qualita- tive, but also quantitative interpretation of MERTIS spectra

Properties of inductance and magnetic penetration depth in (103)-oriented YBa2Cu3O7-delta thin films

We present a study of the anisotropy of the inductance in (103) YBa2Cu3O7-delta (YBCO) films. YBCO superconducting quantum interference devices (SQUIDs) were fabricated by the biepitaxial technique. SQUIDs with (001)- and (103)-oriented YBCO electrodes characterized by different grain-boundary angles were realized on the same chip. Two extrainjection lines were attached to the (103) YBCO electrode. These devices, when operated in current injection mode, allow us to measure the inductance of the (103) YBCO electrode. We have found that the inductance L of the (103) YBCO can differ by a factor of 20 in the two extreme cases: L determined by current transport parallel to the ab planes and L dominated by the transport in the c-axis direction. The full in-plane angular dependence of the inductance has been obtained by considering geometrically identical SQUIDs oriented with different angles with respect to the [100] direction of the (103) film. From these measurements, we have determined the London penetration depths in the ab direction lambda(ab) and the c direction lambda(c) and their temperature dependence

Estimation of surface temperatures on Mercury in preparation of the MERTIS experiment onboard BepiColombo

The Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) is part of the payload on the joint ESA-JAXA BepiColombo Mission, launched in October 2018. The spectrometer is designed to map surface composition, identify rock-forming minerals, map surface mineralogy, and study surface temperature variations. The surface of Mercury undergoes large temperature variations depending on solar irradiation. Mineral spectra show significant changes in spectral features with changing temperature. In preparation of the experiment, we developed a thermal model that calculates surface temperatures based on appropriate insolation conditions and thermo-physical properties. This model has been validated with lunar parameters and hence been applied to the conditions of Mercury. Here we present surface temperature maps based on MESSENGER albedo and topography data. The results have been compared to previous models and measurements of Mercury's surface temperatures. The surface of Mercury undergoes large temperature variations each diurnal period. At the equator temperatures vary between less than 100 K during the night up to 700 K at local noon at longitudes 0° W and 180° W, and up to 570 K at longitudes 90° W and 270° W. Due to the 3:2 spin orbit resonance local noon at longitudes 0° W and 180° W coincide with perihelion, while longitudes 90° W and 270° W experience local noon at aphelion, which results in “hot” and “warm” poles around the equator. At 45° N surface temperatures at local noon reach 645 K (0° W and 180° W) and 510 K (90° W and 270° W)

Properties of inductance and magnetic penetration depth in (103)-oriented YBa2Cu3O7-delta thin films

We present a study of the anisotropy of the inductance in (103) YBa2Cu3O7-delta (YBCO) films. YBCO superconducting quantum interference devices (SQUIDs) were fabricated by the biepitaxial technique. SQUIDs with (001)- and (103)-oriented YBCO electrodes characterized by different grain-boundary angles were realized on the same chip. Two extrainjection lines were attached to the (103) YBCO electrode. These devices, when operated in current injection mode, allow us to measure the inductance of the (103) YBCO electrode. We have found that the inductance L of the (103) YBCO can differ by a factor of 20 in the two extreme cases: L determined by current transport parallel to the ab planes and L dominated by the transport in the c-axis direction. The full in-plane angular dependence of the inductance has been obtained by considering geometrically identical SQUIDs oriented with different angles with respect to the [100] direction of the (103) film. From these measurements, we have determined the London penetration depths in the ab direction lambda(ab) and the c direction lambda(c) and their temperature dependence