Description: The Danube deep-sea fan complex in the north-western Black Sea, with its ancient channel-levee systems, hosts multiple bottom-simulating reflections (BSRs) that have been observedin high-resolution reflection seismic data. The multiple BSRs indicate the presence of gas hydrates and free gas. To image the distribution of free gas and gas hydrates on the western flank of the S2 canyon, simultaneously, ocean bottom seismometer (OBS) data and 2-D high-resolution multichannel reflection seismic (HRMRS) data were acquired during the R/V Maria S. Merian (MSM-34) expedition. Along two parallel HRMRS-OBS profiles we recorded the wave field for a wide range of incidence angles. The velocity-structure models for both, P-and S-wave traveltimes, cover a depth down to 1.2 km, providing seismic velocity information below the BSR. For identification of the P-wave phases from OBS to OBS, we aligned the OBS data at zero offset to the 2-D HRMS data at each OBS location. The P-wave velocities show a gradual increase with depth from 1510 m/s directly beneath the seafloor up to 1900 m/s at 1.2 km depth. As the S-waves travel at slower speed than P-waves, S-waves reflection could be traced only in a smallsource-receiver offset with a maximum of ~0.9 km. We assume the reflection horizon to be the point of P-to-S conversion. Seismic S-wave velocities increase from 140 m/s beneath the seafloor up to 860 m/s at 1.2 km depth. These observations allow the determination of the P-to-S-ratio that decreases from 10.6 beneath the seafloor down to 2.2 at 1.2 km depth. The seismic velocities and P-to-S-ratio exclude the presence of gas hydrates above the BSR, but endorse the accumulation of a low concentration of free gas below. The distribution of the gas is predominately controlled by lithology.

Description: Interest in layered Ruddlesden–Popper (RP) strongly correlated manganites of Pr0.5Ca1.5MnO4 as well as in their thin film polymorphs is motivated by the high temperature of charge orbital ordering above room temperature. The c-axis orientation in epitaxial films is tailored by different SrTiO3 (STO) substrate orientations and CaMnO3 (CMO) buffer layers. Films on STO(110) show in-plane alignment of the c-axis parallel to the [100] direction. On STO(100), two possible directions of the in-plane c-axis lead to a mosaic like, quasi 2D nanostructure, consisting of RP, rock-salt, and perovskite blocks. With the CMO buffer layer, Pr0.5Ca1.5MnO4 epitaxial films with c-axis out-of-plane are realized. Different physical vapor deposition techniques as ion beam sputtering, pulsed laser deposition and metalorganic aerosol deposition are applied in order to distinguish effects of growth conditions from intrinsic epitaxial properties. Despite their very different growth conditions, surface morphology, crystal structure, and orientation of the thin films reveal a high level of similarity as verified by X-ray diffraction, scanning, and high resolution transmission electron microscopy. For different epitaxial relations stress in the films is relaxed by means of modified interface chemistry. The charge ordering in the films occurs at a temperature close to that expected in bulk material.