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Robust engine operation with long maintenance intervals and low emissions is the key to meeting future engine requirements. At the same time, engines should be environmentally friendly, resource-friendly, and cost-effective to produce and operate. To meet these market requirements, a central component in engine development is the ignition system and in particular the spark plug. To increase the maintenance intervals of internal combustion engines, it is necessary to increase spark plug lifetime by reducing spark plug wear. The electrode materials used to date are often expensive and rare, and their mining is not without controversy. Successful use of alternative spark plug electrode materials which are available in large quantities, inexpensive, and more resistant to wear than existing materials with similar ignition behavior would advance engine development so it can meet further economic and environmental requirements. To this end, ceramic spark plug electrodes were investigated to determine their spark and ignition behavior as well as their wear. These materials seem to be an interesting alternative to existing spark plug electrode materials. This paper presents a spark plug with ceramic spark plug electrodes that achieves conditions similar to those of standard spark plugs in terms of secondary voltage trace and ignition behavior. Furthermore, it introduces a sophisticated method for scientific, cost-effective, and application-oriented development. Finally, it provides a promising outlook for the ignition behavior and combustion performance of engines with this spark plug.

Despite growing interest in metastasis-directed therapy (MDT) for prostate cancer (PCa), little is known regarding the feasibility and effectiveness of surgical metastasectomy for isolated lesions. We performed a narrative review of the available evidence supporting metastasectomy for M1b-c lesions in men diagnosed with oligometastatic or oligorecurrent PCa. The case series and case reports we identified indicate that surgical MDT is a safe and feasible treatment option for well-selected patients with a small number of PCa metastases diagnosed via molecular imaging. It is difficult to draw evidence-based conclusions regarding the survival benefit of metastasectomy; however, metastasectomy might lead to a prostate-specific antigen response and could potentially delay systemic therapy in patients with oligometastatic PCa. Prospective studies incorporating novel imaging are needed to better establish the role of metastasectomy for patients with metastatic PCa. PATIENT SUMMARY: We reviewed the evidence on surgical removal of prostate cancer lesions that have spread to the organs (eg, liver and lung) or bone, which are called metastases. Limited results show that this approach is feasible and has favorable outcomes in selected patients.

At low sample voltages, Cl ions may be bidirectionally transferred between a Fe tetraphenylporphyrin (FeTPP) molecule on Au(111) and the tip of a low-temperature scanning tunneling microscope that ...

Many substrates for microelectronic systems contain ceramic/glass layers and metal features (e.g. electrodes, vias, metal pads) built up in a complex 3D architecture. The combination of different materials with distinct thermo-elastic properties may yield significant (local) internal stresses, which are to be superimposed to external thermo-mechanical loads in service. Due to the various material junctions, interfaces, etc, failure of these multilayer systems can hardly be predicted. In this work, a strategy is proposed to quantify the effect of architecture and loading conditions on the mechanical reliability of ceramic-based substrates. Model ceramic structures containing important design features (e.g. inner electrode, via, top metallization) were fabricated and tested in different environments (i.e. humid or dry conditions) under uniaxial as well as biaxial bending. Significant difference in the characteristic strength between ∼260 MPa and ∼620 MPa were measured, associated with the particular architectural feature, type of loading, and/or environment.

The competition between honeycomb and hexagonal tiling of molecular units can lead to large honeycomb superstructures on surfaces. Such superstructures exhibit pores that may be used as 2D templates for functional guest molecules. Honeycomb superstructures of molecules that comprise a C3 symmetric platform on Au(111) and Ag(111) surfaces are presented. The superstructures cover nearly mesoscopic areas with unit cells containing up to 3000 molecules, more than an order of magnitude larger than previously reported. The unit cell size may be controlled by the coverage. A fairly general model was developed to describe the energetics of honeycomb superstructures built from C 3 symmetric units. Based on three parameters that characterize two competing bonding arrangements, the model is consistent with the present experimental data and also reproduces various published results. The model identifies the relevant driving force, mostly related to geometric aspects, of the pattern formation., Molecular honeycomb superstructures were investigated using scanning tunneling microscopy, covering nearly mesoscopic areas and with unit cells containing up to 3000 molecules. A fairly general model was developed that describes the energetics of such structures and show that their sizes can be controlled by coverage.

Molecular rotors have attracted considerable interest for their prospects in nanotechnology. However, their adsorption on supporting substrates, where they may be addressed individually, usually modifies their properties. Here, we investigate the switching of two closely related three-state rotors mounted on platforms on Au(111) using low-temperature scanning tunneling microscopy and density functional theory calculations. Being physisorbed, the platforms retain important gas-phase properties of the rotor. This simplifies a detailed analysis and permits, for instance, the identification of the vibrational modes involved in the rotation process. The symmetry provided by the platform enables active control of the rotation direction through electrostatic interactions with the tip and charged neighboring adsorbates. The present investigation of two model systems may turn out useful for designing platforms that provide directional rotation and for transferring more sophisticated molecular machines from the gas phase to surfaces.

The Co-based complex [Co(H

The journal of physical chemistry / C 125(25), 14105-14116 (2021). doi:10.1021/acs.jpcc.1c03527, Spin-crossover complexes in direct contact with substrates have sparked considerable interest, in particular, in view of their potential applications in molecular electronics. While a huge number of spin-crossover complexes is available, many of them are not robust enough to withstand the sample preparation and/or the interaction with the substrate. The techniques usually employed for these investigations, namely, near-edge X-ray absorption fine structure spectroscopy and low-temperature scanning tunneling microscopy, are not adapted for systematic studies because of the limited access to synchrotron-radiation facilities and complexity of the (indirect) spin determination, respectively. Here, we detail a methodology using a (more) commonly available technique, namely, vacuum ultraviolet (angle-resolved) photoemission spectroscopy, to determine the spin state of layers of three different spin-crossover complexes with thicknesses down to the submonolayer regime. We present an approach to determine the thicknesses of the investigated layers, relying on the inelastic mean free path of electrons determined from combined photoemission and X-ray absorption measurements. We report on the high-spin to low-spin relaxation dynamics of spin-crossover (SCO) layers and the influence of the ultraviolet light on these dynamics. While the observed relaxation processes occur on a timescale on the order of minutes, probing spin-state dynamics on the picosecond timescale is foreseeable with pump–probe photoemission spectroscopy., Published by Soc., Washington, DC

The integrity and functionality of spin-crossover complexes, which exhibit an intrinsic magnetic bistability, is generally lost on metal surfaces, with only rare exceptions. In contrast, robust metal-organic complexes such as metal porphyrins rely on external ligands to induce spin switching. We introduce a new class of spin switches utilising the mechanical movement of an axial pyridine ligand strapped to a Ni porphyrin ring. A particular design of the strap ensures a coupling between the shape of the porphyrin, the coordination number and the spin of the Ni center. The relation between the coordination and the spin state is evidenced in the crystalline state and on a Ag(111) surface using near-edge x-ray absorption fine structure spectroscopy. Reversible switching of individual complexes on Ag(111) is demonstrated using low-temperature scanning microscopy. Besides the promises in molecular spintronics, this class of systems may turn useful to control the catalytic reactivity of surfaces.

The current I through nickelocene molecules and its noise are measured with a low-temperature scanning tunneling microscope on a Cu(100) substrate. Density functional theory calculations and many-body modeling are used to analyze the data. During contact formation, two types of current evolution are observed, namely an abrupt jump to contact and a smooth transition. These data along with conductance spectra (dI/dV) recorded deep in the contact range are interpreted in terms of a transition from a spin-1 to a spin-12 state that is Kondo-screened. Many-body calculations show that the smooth transition is also consistent with a renormalization of spin excitations of a spin-1 molecule by Kondo exchange coupling. The shot noise is significantly reduced compared to the Schottky value of 2eI. The noise can be described in the Landauer picture in terms of the spin polarization of the transmission of ≈35% through two degenerate dπ-orbitals of the nickelocene molecule., This work has been supported by the Deutsche Forschungsgemeinschaft, project BE 2132/8. N.L. is grateful for the financial support from MICINN (RTI2018- 097895-B-C44). D.J. acknowledges funding by the grant “Grupos Consolidados UPV/EHU del Gobierno Vasco” (IT1249-19).

This article presents the experimental results of a novel Power-to-Gas (PtG) concept combining a pressurized high-temperature steam electrolysis (SOEC) and a CO2-methanation module in stand-alone and thermally integrated operation. For the electrolyser, steam conversion and energy demands at pressures up to 15 bar were examined. In terms of the methanation module, cooling performance, steam production and product gas quality were of main interest. Additionally, temperature profiles inside the fixed beds were gathered by a multipoint thermocouple at pressures up to 30 bar and load modulations from 20 to 100%. With less than 2 vol% H2 and over 97 vol% CH4 in the finally produced synthetic natural gas (SNG), it can be directly injected into the existing German natural gas grid without further gas cleaning and without capacity limitations. The achieved overall PtG efficiency of 76% is significantly higher than state of the art plants and has the potential to reach 80% in industrial scale.

The outstanding functional properties of single crystals used in many engineering applications often rely on their surface quality. The associated grinding process in single crystals is known to introduce surface or sub-surface defects (cracks), which may compromise the functionality and/or structural integrity of the final device. The small size of such defects often yields relatively high strength values, but also usually large scatter which implies low reliability. The aim of this work is to analyze the onset of surface contact damage in single crystals with respect to crystal orientation and elastic properties. LiTaO3 and LiNbO3 anisotropic single crystal samples are investigated using nanoindentation techniques and focused ion beam based sub-surface analyses. Experimental findings show that the onset of damage is correlated to weaker cleavage planes. At this stage also traces of plastic deformation on the contact surface due to twinning are observed. Further load increase revealed contact cracks in both materials; their morphology and extension being related to the orientation of the cleavage planes and elastic properties of the crystals. Our results advance the understanding of damage in anisotropic materials such as LiTaO3 and LiNbO3, and can generally be utilized to assess the onset of damage in other brittle materials. Keywords: Nanoindentation, Single crystals, Anisotropy, Pop-in, Twinning, Cracking

The search of new designs for communication technologies is driven by the required high data transfer rates. Piezoelectric single crystals such as LiTaO3 and LiNbO3 have qualified as materials for efficient and precise frequency filters also considered for the new 5G standards. To ensure optimal high frequency functionality, single crystal wafers are grown and cut in particular directions. However, due to the high anisotropic physical properties of these brittle materials, the structural integrity and reliability of devices are affected by the crystal orientation with respect to the occurring thermo-mechanical stresses. In this work, the anisotropic fracture response of LiTaO3 and LiNbO3 single crystals is investigated through combination of (i) toughness measurements in notched micro-cantilevers along weak cleavage planes and (ii) atomistic modelling of cleavage fracture energies using density functional theory. It is demonstrated that differences in fracture behaviour between LiTaO3 and LiNbO3 can be explained by the stronger chemical bonding in LiTaO3 as compared to LiNbO3 within the loaded crystallographic planes. The knowledge on the alignment of tough as well as weak planes (i.e. cleavage planes) can be used to tailor the design of single crystal based functional components, aiming to exhibit enhanced mechanical reliability without compromising the functionality.

This work deals with the coupling between high temperature steam electrolysis using solid oxide cells (SOEC) and carbon dioxide methanation to produce a synthetic natural gas (SNG) directly injecta...

The journal of physical chemistry letters 9(7), 1491 - 1496 (2018). doi:10.1021/acs.jpclett.8b00338, Understanding and controlling the spin-crossover properties of molecular complexes can be of particular interest for potential applications in molecular spintronics. Using near-edge X-ray absorption fine structure spectroscopy, we investigated these properties for a new vacuum-evaporable Fe(II) complex, namely [Fe(pypyr(CF$_3$)$_2$)$_2$(phen)] (pypyr = 2-(2′-pyridyl)pyrrolide, phen = 1,10-phenanthroline). We find that the spin-transition temperature, well above room temperature for the bulk compound, is drastically lowered for molecules arranged in thin films. Furthermore, while within the experimentally accessible temperature range (2 K < T < 410 K) the bulk material shows indication of neither light-induced excited spin-state trapping nor soft X-ray-induced excited spin-state trapping, these effects are observed for molecules within thin films up to temperatures around 100 K. Thus, by arranging the molecules into thin films, a nominal low-spin complex is effectively transformed into a spin-crossover complex., Published by ACS, Washington, DC

Interconnected molecular magnetic centers on metallic surfaces are of interest for molecular spintronics. Complexes composed of two or three cobaltocene units linked by naphthalene or benzene groups are successfully deposited on Au(111) and Cu(111) by sublimation and electrospray deposition. Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate the deposited compounds and their spin state. Although all molecules are composed of the same magnetic cobaltocene unit, only one compound shows a zero-bias feature compatible with a Kondo resonance, whose amplitude varies from molecule to molecule. The amplitude variation and its absence for the other investigated complexes are attributed to different molecule–substrate coupling, which is strongly influenced by the linker. Parameters influencing the molecule–substrate coupling and molecular properties are extracted from the experimental data. These key parameters should be considered for future strategies of interconnected magn...

The strength distribution and fracture behaviour of miniaturized Lithium niobate (LiNbO 3 ) and Lithium tantalate (LiTaO 3 ) single crystals were assessed under biaxial bending. The susceptibility of these materials to environmental assisted cracking (SCCG) was studied by means of constant cross-head displacement rate experiments in air and in water. Two different sample sizes were tested and compared to assess the Weibull volume effect. Experimental results showed a significant difference in strength, LiNbO 3 being weaker than LiTaO 3 . No apparent SCCG and no volume effect on strength were found. A different distribution to Weibull behaviour was observed in LiNbO 3 . Fractography showed differences in the fracture patterns, due to the different cutting orientation of the two investigated materials with respect to the loading plane. New cleavage planes were identified as {10.1} for LiNbO 3 and {1 2 ¯ .3} for LiTaO 3 . Fracture surfaces of LiNbO 3 revealed surface damage, which may be responsible for the lower strength compared to LiTaO 3 .

Functional components are commonly fabricated combining a ceramic substrate with external and/or internal metallization. Different layers are printed and fired onto the ceramic part to provide the component with a functionality. As a result of the combination of materials with different coefficients of thermal expansion, internal stresses during the fabrication steps may lead to cracks and/or reduce the strength. In this work, several architectures combining metal and glass layers on the surface of ZnO substrates were analyzed to identify critical fabrication steps in functional co-fired multilayer ceramics. Three-point bending tests were performed on samples taken after different process steps. Experimental results showed a strong effect of the layered architecture on the strength distributions: details of geometrical designs can have a dramatic impact on the strength. Fractographic analyses and ex-situ Focused Ion Beam experiments in pre-loaded samples were the key to assess the location of failure and predict critical configurations.

The switching between two spin states makes spin-crossover molecules on surfaces very attractive for potential applications in molecular spintronics. Using scanning tunneling microscopy, the successful deposition of [Fe(pap)2]+ (pap = N-2-pyridylmethylidene-2-hydroxyphenylaminato) molecules on Cu2N/Cu(100) surface is evidenced. The deposited FeIII spin-crossover compound is controllably switched between three different states, each of them exhibiting a characteristic tunneling conductance. The conductance is therefore employed to readily read the state of the molecules. A comparison of the experimental data with the results of density functional theory calculations reveals that all Fe(pap)2 molecules are initially in their high-spin state. The two other states are compatible with the low-spin state of the molecule but differ with respect to their coupling to the substrate. As a proof of concept, the reversible and selective nature of the switching is used to build a two-molecule memory.

Spin-crossover molecules on metallic substrates have recently attracted considerable interest for their potential applications in molecular spintronics. Using scanning tunneling microscopy, we evidence the first successful deposition of a charged FeIII spin-crossover complex, [Fe(pap)2]+ (pap = N-2-pyridylmethylidene-2-hydroxyphenylaminato), on Au(111). Furthermore, the bulk form of the molecules is stabilized by a perchlorate counterion, which depending on the deposition technique may affect the quality of the deposition and the measurements. Finally, we evidence switching of the molecules on Au(111).

ECS journal of solid state science and technology 9(6), 061005 - (2020). doi:10.1149/2162-8777/ab9e18, The influence of the contracted corrole macrocycle, in comparison to the larger porphyrin macrocycle, on the electronic structure of nickel was studied with X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Synthesis and in situ characterization of the Ni complexes of octaethylporphyrin (NiOEP) and hexaethyldimethylcorrole (NiHEDMC) were performed in ultra-high vacuum. XPS and NEXAFS spectra reveal a +2 oxidation state and a low-spin d8 electron configuration of Ni in both complexes, despite the formal trianionic nature of the corrole ligand. UPS, in combination with density functional theory (DFT) calculations, support the electronic structure of a Ni(II) corrole with a π-radical character of the ligand. The NEXAFS spectra also reveal differences in the valence electronic structure, which are attributed to the size mismatch between the small Ni(II) center and the larger central cavity of NiOEP. Analysis of the gas-phase structures shows that the Ni−N bonds in NiOEP are 4%–6% longer than those in NiHEDMC, even when NiOEP adopts a ruffled conformation. The individual interactions that constitute the Ni−ligand bond are altogether stronger in the corrole complex, according to bonding analysis within the energy decomposition analysis and the natural orbitals for chemical valence theory (EDA-NOCV)., Published by ECS, Pennington, NJ

The coordination sphere of the Fe(II) terpyridine complex 1 is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa‐aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff‐base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed‐phase HPLC enables the isolation of the all‐trans isomer of the Fe(II) terpyridine complex 1, which is fully characterized. While temperature independent low‐spin states were recorded with superconducting quantum interference device (SQUID) measurements for both, the open precursor 8 and the interlinked complex 1, evidence of the increased rigidity of the ligand sphere in 1 was provided by proton T$_{2}$ relaxation NMR experiments. The ligand sphere fixation in the macrocyclized complex 1 even reaches a level resisting substantial deformation upon deposition on an Au(111) surface, as demonstrated by its pristine form in a low temperature ultra‐high vacuum scanning tunneling microscope experiment.

Molecular spin switches are attractive candidates for controlling the spin polarization developing at the interface between molecules and magnetic metal surfaces1,2, which is relevant for molecular spintronics devices3–5. However, so far, intrinsic spin switches such as spin-crossover complexes have suffered from fragmentation or loss of functionality following adsorption on metal surfaces, with rare exceptions6–9. Robust metal–organic platforms, on the other hand, rely on external axial ligands to induce spin switching10–14. Here we integrate a spin switching functionality into robust complexes, relying on the mechanical movement of an axial ligand strapped to the porphyrin ring. Reversible interlocked switching of spin and coordination, induced by electron injection, is demonstrated on Ag(111) for this class of compounds. The stability of the two spin and coordination states of the molecules exceeds days at 4 K. The potential applications of this switching concept go beyond the spin functionality, and may turn out to be useful for controlling the catalytic activity of surfaces15. Spin-crossover complexes often lose their functionality upon adsorption on metal surfaces. Here, a metal–organic complex adsorbed on a silver surface undergoes reversible interlocked spin and coordination switching, which is enabled by an intramolecular feedback mechanism controlling the position of an axial ligand strapped to the complex.

This article presents the simulation-based analysis of experimental results from a catalytic fixed-bed reactor for the methanation of CO2. During previously published experiments, temperature profiles inside bidisperse catalyst-silicon carbide fixed-beds were gathered and reactant conversions at the reactor outlet measured. On the basis of the temperature profiles along the fixed-bed length and outlet reactant conversions, a procedure for the numerical characterisation of these results was developed. Primary parameters like the inserted multipoint thermocouple and the heat transfer coefficient between reactor wall and surrounding boiling water cooling are systematically investigated. Concerning the binary bidisperse fixed-beds of porous catalyst cylinders and highly thermal conductive silicon carbide, a simple numerical method for the determination of the effective heat conductivity of the bed is presented. The modelling of effective reaction rates within an industrial sized catalyst and reactor is a non-trivial task, due to interlinking aspects like intrinsic reaction rate and internal and external transport limitations. Intrinsic reaction rate, internal and external transport limitations are linked, what makes a separate investigation challenging. Thus, a step by step analysis is presented and the single effects investigated in detail. From the results of the stepwise numerical characterisation, an excellent agreement between experiments and numerics was reached. Additionally, a novel partially resolved 3D fixed-bed reactor model is presented and selected results like particle overheating presented. Overall the present numerical investigations provided a deep insight into the methanation of CO2 in a cooled fixed-bed reactor.

Shikimic-acid and beta-carotene molecules were investigated on various metallic substrates using scanning tunneling microscopy at ∼5 K. We studied the potential ability of these metal-free organic molecules to be switched into a magnetic state as it was recently evidenced for retinoic acid and cholesterol on Au(111). While our attempts to generate spin within shikimic-acid and beta-carotene molecules proved unsuccessful, switching attempts for different molecule/substrate pairs were thoroughly analyzed so as to tentatively elucidate the underlying causes of the vain attempts. We speculate that, by avoiding the identified causes, other organic molecule/substrate pairs can be found for spin manipulation.

A high spin polarization of states around the Fermi level, EF, at room temperature has been measured in the past at the interface between a few molecular candidates and the ferromagnetic metal Co. Is this promising property for spintronics limited to these candidates? Previous reports suggested that certain conditions, such as strong ferromagnetism, i.e., a fully occupied spin-up d band of the ferromagnet, or the presence of π bonds on the molecule, i.e., molecular conjugation, needed to be met. What rules govern the presence of this property? We have performed spin-resolved photoemission spectroscopy measurements on a variety of such interfaces. We find that this property is robust against changes to the molecule and ferromagnetic metal's electronic properties, including the aforementioned conditions. This affirms the generality of highly spin-polarized states at the interface between a ferromagnetic metal and a molecule and augurs bright prospects toward integrating these interfaces within organic spintronic devices.

The properties of Fe(1,10-phenanthroline)2(NCS)2 (Fe-phen) molecules deposited on Co/Cu(111) are studied with scanning tunneling microscopy (STM) operated in ultrahigh vacuum at low temperature (4 K) and ab initio calculations. Both the experimental and theoretical results are used to identify the high-spin (HS) state of Fe-phen. Additionally, the calculations reveal a strong spin-polarization of the density of states (DOS) and is validated experimentally using the spin sensitivity of spin-polarized STM. Finally, it is shown that the magnetic moment of the Fe-ion within HS Fe-phen is strongly magnetically coupled to the underlying magnetic Co through the NCS groups. These findings enable promising spintronic perspectives.

The present study highlighted the importance of equipment design for the experimental differentiation of thermal and electric field effects during ohmic heating. Based on these findings, a specifically designed setup was capable of reducing temperature inhomogeneities of conventional and ohmic heating, thus allowing for a maximum comparability of the processes. The effects of the treatments were evaluated by determination of inactivation kinetics, using different microorganisms, i.e. Microbacterium lacticum, Escherichia coli, Listeria innocua, Staphylococcus carnosus, Saccharomyces cerevisiae, and Rhodotorula glutinis in neutral as well as acidic (pH 3.8) solutions. Selected kinetics were further analyzed by flow cytometry, using SYBR green and propidium iodide staining. Based on comparable T, t-profiles and plate counts, conventional and ohmic heating were shown to be capable of effectively inactivating all tested microorganisms (max. 2.5–6.5 log), depending on treatment intensity (2.5 kW, up to 140 s) and pH level. No additional, non-thermal inactivation effects were determined for ohmic heating treatments, independent of the used matrix, pulse repetition rate/frequency, or waveform. Industrial relevance Ohmic heating is an alternative thermal preservation treatment increasingly used in the food and biotechnological industries for sensitive matrices, which are otherwise difficult to thermally process. It is able to overcome heat transfer limitations usually present in conventional thermal treatments, by application of an electric current flow through the product. The present paper contributes to better understand preservation by electrotechnologies and to the elucidation of inactivation mechanisms by ohmic heating. Thus, the understanding of the effects of ohmic heating on microorganisms is increased, which is crucial for industrial implementation of the technology and the corresponding process design.

International audience; Spin-crossover complexes are attractive for their spin-switching functionality. However, only a few compounds have been found to remain intact in direct contact to metal surfaces. For the design of new spin-crossover complexes, it is important to understand the mechanisms leading to fragmentation. Here, we investigate, using low-temperature scanning tunneling microscopy along with density functional theory calculations, two Fe-(terpyridine) 2 complexes deposited on Au(111) by electro-spray ionization with in-line mass selection. Only fragments of the first compound are observed on the surface, while the second compound is strongly flattened. On the basis of a detailed analysis of the adsorbates on the surface, possible mechanisms for the fragmentation and molecular distortion are proposed.

The bistability of spin-crossover complexes on surfaces is of great interest for potential applications. Using X-ray absorption spectroscopy, we investigated the properties of [Fe(pypyr(CF$_3$)$_2$)$_2$(phen)] (pypyr = 2-(2′-pyridyl)pyrrolide, phen = 1,10-phenanthroline), a vacuum-evaporable Fe(II) complex, in direct contact to a set of substrates. The electronic properties of these substrates range from metallic to semiconducting. While dissociation is observed on metal surfaces, efficient light-induced switching is realized on semimetallic and semiconducting surfaces. This indicates that the density of states of the substrate at the Fermi level plays a role for the integrity and functionality of the adsorbed compound. In an intermediate case, namely, [Fe(pypyr(CF$_3$)$_2$)$_2$(phen)] on graphene/Ni(111), functional and dissociated species are found to coexist. This result indicates that some previous studies may deserve to be reconsidered because the possibility of coexisting intact and fragmented spin-crossover complexes was neglected.

Inert metal surfaces present more chances of hosting organic intact radicals than other substrates, but large amounts of delocalized electronic states favor charge transfer and thus spin quenching. Lowering the molecule-substrate interaction is a usual strategy to stabilize radicals on surfaces. In some works, thin insulating layers were introduced to provide a controllable degree of electronic decoupling. Recently, retinoid molecules adsorbed on gold have been manipulated with a scanning tunneling microscope (STM) to exhibit a localized spin, but calculations failed to find a radical derivative of the molecule on the surface. Now the formation of a neutral radical spatially localized in a tilted and lifted cyclic end of the molecule is presented. An allene moiety provokes a perpendicular tilt of the cyclic end relative to the rest of the conjugated chain, thus localizing the spin of the dehydrogenated allene in its lifted subpart. DFT calculations and STM manipulations give support to the proposed mechanism., M.‐L.B. thanks the national computational center CINES, and TGCC (Grant 2017‐ [GENCI project: A0010807364]) for a computer grant and acknowledges the Mercator fellowship of SFB 677 in CAU Kiel. N.L. acknowledges financial support from MINECO (MAT2015‐66888‐C3‐2‐R) and FEDER funds, and he is thankful to the Mercator fellowship of SFB 677 in CAU Kiel. M.G. acknowledges financial support of SFB 677. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 766726.

In the scanning tunnelling microscope, the many-body Kondo effect leads to a zero-bias feature of the differential conductance spectra of magnetic adsorbates on surfaces. The intrinsic line shape of this Kondo resonance and its temperature dependence in principle contain valuable information. We use measurements on a molecular Kondo system, all- trans retinoic acid on Au(1 1 1), and model calculations to discuss the role of instrumental broadening. The modulation voltage used for the lock-in detection, noise on the sample voltage, and the temperature of the microscope tip are considered. These sources of broadening affect the apparent line shapes and render difficult a determination of the intrinsic line width, in particular when variable temperatures are involved.

We performed SQUID and FMR magnetometry experiments to clarify the relationship between two reported magnetic exchange effects arising from interfacial spin-polarized charge transfer within ferromagnetic metal (FM)/molecule bilayers: the magnetic hardening effect, and spinterface-stabilized molecular spin chains. To disentangle these effects, both of which can affect the FM magnetization reversal, we tuned the metal phthalocyanine molecule central site's magnetic moment to selectively enhance or suppress the formation of spin chains within the molecular film. We find that both effects are distinct, and additive. In the process, we 1) extended the list of FM/molecule candidate pairs that are known to generate magnetic exchange effects, 2) experimentally confirmed the predicted increase in anisotropy upon molecular adsorption; and 3) showed that spin chains within the molecular film can enhance magnetic exchange. This magnetic ordering within the organic layer implies a structural ordering. Thus, by distengangling the magnetic hardening and exchange bias contributions, our results confirm, as an echo to progress regarding inorganic spintronic tunnelling, that the milestone of spintronic tunnelling across structurally ordered organic barriers has been reached through previous magnetotransport experiments. This paves the way for solid-state devices studies that exploit the quantum physical properties of spin chains, notably through external stimuli., None

Functional components are commonly fabricated combining a ceramic substrate with external and/or internal metallization (e.g. metal electrodes, vias, contact pads, etc.) using a tape casting process. Different layers are printed and/or fired (e.g. up to 800°C) onto the ceramic part to provide the component with a (certain) functionality. As a result of the combination of different materials (e.g. ceramic, glass, metal alloys) with different coefficients of thermal expansion, internal stresses may arise during the different fabrication steps. Although some of these tensile residual stresses may relax due to plastic deformation of metallic materials, stress concentrations generated in material junctions or terminations (imposed by geometrical constrains) may lead to cracks and/or reduce the component strength.In this work different architectures combining metal and glass layers on the surface of ZnO substrates were investigated experimentally and numerically in order to identify weak points in commercial components. Mechanical testing using three-point-bending was performed on samples taken after different steps. A FE model was developed to (i) calculate residual stresses generated during the manufacturing process, and (ii) simulate the propagation of initial crack/defect during manufacturing. Experimental results were compared with numerical predictions. These results in combination with fractographic analyses were used to validate the finite element model in order to assess location of failure.

Molecular semiconductors may exhibit antiferromagnetic correlations well below room temperature. Although inorganic antiferromagnetic layers may exchange bias single-molecule magnets, the reciprocal effect of an antiferromagnetic molecular layer magnetically pinning an inorganic ferromagnetic layer through exchange bias has so far not been observed. We report on the magnetic interplay, extending beyond the interface, between a cobalt ferromagnetic layer and a paramagnetic organic manganese phthalocyanine (MnPc) layer. These ferromagnetic/organic interfaces are called spinterfaces because spin polarization arises on them. The robust magnetism of the Co/MnPc spinterface stabilizes antiferromagnetic ordering at room temperature within subsequent MnPc monolayers away from the interface. The inferred magnetic coupling strength is much larger than that found in similar bulk, thin or ultrathin systems. In addition, at lower temperature, the antiferromagnetic MnPc layer induces an exchange bias on the Co film, which is magnetically pinned. These findings create new routes towards designing organic spintronic devices.

We deploy topographical and spectroscopic techniques to show that a strongly spin-polarized interface arises between ferromagnetic cobalt and an amorphous carbon layer. Scanning tunneling microscopy and spectroscopy show how a semiconducting carbon film with a low band gap of about 0.4 eV is formed atop the metallic interface. To understand how the cobalt/carbon interface is formed, we used X-ray photoemission spectroscopy to study the hybridization state of carbon. We find that the semiconducting layer consists mainly of sp(2)-bonded carbon atoms with a sp(2)-to-sp(3) ratio between 1.4 and 1.8. The spin-polarized properties of the cobalt/carbon interface are studied by spin-resolved photoemission spectroscopy. We observe interface states close to the Fermi energy that are not exclusive to cobalt. These electronic states reveal a high degree of spin polarization at room temperature. (C) 2015 Elsevier Ltd. All rights reserved.

The German ‘‘Energiewende’’ is heavily based on electric power and, therefore, requests solutions to serve non-electric energy uses and to store electric energy in large scale. Synthetic natural gas (SNG) produced with hydrogen from water electrolysis and with CO2 from mainly renewable sources is one approach. For the catalytic SNG production efficient removal and utilization of the reaction heat is the main issue. A metallic honeycomb-like carrier-based reactor proved in laboratory scale to match this challenge. This type of reactor shows good heat conductivity and enables optimized operation. In the EU-funded project Store&Go the honeycomb methanation is scaled up to MW-scale. For this, heat transfer and kinetic data were determined experimentally and used in CFD calculations for the reactor design. Finally a SNG plant with 1MW feed-in will be built and fully integrated operation will be shown.

The Kondo effect of adatoms on surfaces may to some extent be controlled by manipulating their electronic and geometric environment. Results are presented from artificial structures like quantum well systems, from arrangements of single atoms made with a scanning tunneling microscope, and from custom-made molecules. Spin-orbit coupling at single adatoms is probed via measurements of the anisotropic magnetoresistance, in particular in single atom contacts. Such junctions are also investigated with respect to the current shot noise, which is influenced by the electron spin.

Magnetic sandwich complexes are of particular interest for molecular spintronics. Using scanning tunneling microscopy, we evidence the successful deposition of 1,3,5-tris(η6-borabenzene-η5-cyclopentadienylcobalt) benzene, a molecule composed of three connected magnetic sandwich units, on Cu(111). Scanning tunneling spectra reveal two distinct spatial-dependent narrow resonances close to the Fermi level for the trimer molecules as well as for molecular fragments composed of one and two magnetic units. With the help of density functional theory, these resonances are interpreted as two Kondo resonances originating from two distinct nondegenerate d-like orbitals. These Kondo resonances are found to have defined spatial extents dictated by the hybridization of the involved orbitals with that of the ligands. These results opens promising perspectives for investigating complex Kondo systems composed of several “Kondo” orbitals.

Heptacene was generated by surface-assisted didecarbonylation of an α-diketone precursor on a Ag(111) surface. Monitoring of the surface reaction and characterization of the adsorbed heptacene was performed with scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and density functional theory (DFT) calculations. The surface-assisted formation of heptacene occurs around 460 K. Both the heptacene and the precursor molecules are oriented along the high-symmetry directions of the (111) surface and their molecular π systems face towards the substrate. The interaction with the Ag(111) substrate is not laterally uniform, but appears to be strongest on the central part of the molecule, in line with the expectations from Clar's rule. In the STM images, heptacene shows a dumbbell shape, which may correspond to the substantial out-of-plane deformations of heptacene on Ag(111). As revealed by DFT, the center of the molecule is closer to the surface than the outer parts. In addition, the inner rings are most affected by charge redistribution between surface and molecule. Heptacene acts as an acceptor and receives a negative charge of -0.6e from the Ag(111) surface. Since vacuum-sublimable α-diketone precursors for even larger acenes are available, the approach is promising for the on-surface synthesis of higher acene homologues such as octacene and nonacene.

Spin-crossover molecules on metallic substrates have recently attracted considerable interest for their potential applications in molecular spintronics. Using scanning tunneling microscopy, we evidence the first successful deposition of a charged Fe

Spin-polarized charge transfer between a ferromagnet and a molecule can promote molecular ferromagnetism 1, 2 and hybridized interfacial states3, 4. Observations of high spin-polarization of Fermi level states at room temperature5 designate such interfaces as a very promising candidate toward achieving a highly spin-polarized, nanoscale current source at room temperature, when compared to other solutions such as half-metallic systems and solid-state tunnelling over the past decades. We will discuss three aspects of this research. 1) Does the ferromagnet/molecule interface, also called an organic spinterface, exhibit this high spin-polarization as a generic feature? Spin-polarized photoemission experiments reveal that a high spin-polarization of electronics states at the Fermi level also exist at the simple interface between ferromagnetic cobalt and amorphous carbon6. Furthermore, this effect is general to an array of ferromagnetic and molecular candidates7. 2) Integrating molecules with intrinsic properties (e.g. spin crossover molecules) into a spinterface toward enhanced functionality requires lowering the charge transfer onto the molecule8 while magnetizing it1,2. We propose to achieve this by utilizing interlayer exchange coupling within a more advanced organic spinterface architecture. We present results at room temperature across the fcc Co(001)/Cu/manganese phthalocyanine (MnPc) system9. 3) Finally, we discuss how the Co/MnPc spinterface’s ferromagnetism stabilizes antiferromagnetic ordering at room temperature onto subsequent molecules away from the spinterface, which in turn can exchange bias the Co layer at low temperature10. Consequences include tunnelling anisotropic magnetoresistance across a CoPc tunnel barrier11. This augurs new possibilities to transmit spin information across organic semiconductors using spin flip excitations12.