408 research outputs found
Determination of spin-dependent Seebeck coefficients of CoFeB/MgO/CoFeB magnetic tunnel junction nanopillars
No full textLiebing N, Serrano-Guisan S, Rott K, et al. Determination of spin-dependent Seebeck coefficients of CoFeB/MgO/CoFeB magnetic tunnel junction nanopillars. Journal of Applied Physics. 2012;111(7): 07C520
A Structurally Characterized Organometallic Plutonium(IV) Complex
No full textbibtex: ISI:000399384700030 bibtex\location:'POSTFACH 101161, 69451 WEINHEIM, GERMANY',publisher:'WILEY-V C H VERLAG GMBH',type:'Article',affiliation:'Walter, O (Reprint Author), European Commiss, Joint Res Ctr, Directorate Nucl Safety & Secur G, POB 2340, D-76125 Karlsruhe, Germany. Vogt, J; Edelmann, FT (Reprint Author), Otto von Guericke Univ, Inst Chem, Univ Pl 2, D-39106 Magdeburg, Germany. Maron, L (Reprint Author), Univ Toulouse, INSA, CNRS, Lab Phys & Chim Nanoobjets LPCNO,UMR5215, 135 Ave Rangueil, F-31077 Toulouse 4, France. Apostolidis, Christos; Walter, Olaf, European Commiss, Joint Res Ctr, Directorate Nucl Safety & Secur G, POB 2340, D-76125 Karlsruhe, Germany. Vogt, Jochen; Liebing, Phil; Edelmann, Frank T., Otto von Guericke Univ, Inst Chem, Univ Pl 2, D-39106 Magdeburg, Germany. Maron, Laurent, Univ Toulouse, INSA, CNRS, Lab Phys & Chim Nanoobjets LPCNO,UMR5215, 135 Ave Rangueil, F-31077 Toulouse 4, France.','author-email':'[email protected] [email protected] [email protected] [email protected]',da:'2018-12-05','doc-delivery-number':'ES2UZ',eissn:'1521-3773','funding-acknowledgement':'Otto-von-Guericke-Universitat Magdeburg','funding-text':'We thank the Otto-von-Guericke-Universitat Magdeburg for general financial support.','journal-iso':'Angew. Chem.-Int. Edit.','keywords-plus':'TRIS(ETA-5-CYCLOPENTADIENYL) ACTINIDE COMPLEXES; FOCK PERTURBATION-THEORY; BUILDING-BLOCK APPROACH; F-ORBITAL COVALENCY; SANDWICH COMPLEXES; ELECTRONIC-STRUCTURE; CRYSTAL-STRUCTURE; CYCLOOCTATETRAENYL COMPLEXES; TH-PU; ACTINOCENES','number-of-cited-references':'69',oa:'Other Gold, Green Published','orcid-numbers':'Edelmann, Frank T./0000-0001-5209-0018 walter, olaf/0000-0002-2679-1715 Liebing, Phil/0000-0002-4660-1691','research-areas':'Chemistry','times-cited':'8','unique-id':'ISI:000399384700030','usage-count-last-180-days':'2','usage-count-since-2013':'23','web-of-science-categories':'Chemistry, Multidisciplinary'\International audienceThe blood-red plutonocene complex Pu(1,3-COT `')(1,4-COT `') (4; COT `' = eta(8)-bis(trimethylsilyl) cyclooctatetraenyl) has been synthesized by oxidation of the anionic sandwich complex Li[Pu(1,4-COT `')(2)] (3) with anhydrous cobalt(II) chloride. The first crystal structure determination of an organoplutonium(IV) complex revealed an asymmetric sandwich structure for 4 where one COT `' ring is 1,3-substituted while the other retains the original 1,4-substitution pattern. The electronic structure of 4 has been elucidated by a computational study, revealing a probable cause for the unexpected silyl group migration
Tunneling magneto thermocurrent in CoFeB/MgO/CoFeB based magnetic tunnel junctions
No full textLiebing N, Serrano-Guisan S, Krzysteczko P, et al. Tunneling magneto thermocurrent in CoFeB/MgO/CoFeB based magnetic tunnel junctions. Applied Physics Letters. 2013;102(24): 242413.We study the tunneling magneto thermopower and tunneling magneto thermocurrent of CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJ). The devices show a clear change of the thermoelectric properties upon reversal of the magnetisation of the CoFeB layers from parallel to the antiparallel orientation. When switching from parallel to antiparallel the thermopower increases by up to 55% whereas the thermocurrent drops by 45%. These observations can be well explained by the Onsager relations taking into account the tunneling magneto resistance of the MTJ. These findings contrast previous studies on Al2O3 based MTJ systems, revealing tunneling magneto thermo power but no tunneling magneto thermocurrent. (C) 2013 AIP Publishing LLC
Tunneling Magnetothermopower in Magnetic Tunnel Junction Nanopillars
No full textLiebing N, Serrano-Guisan S, Rott K, et al. Tunneling Magnetothermopower in Magnetic Tunnel Junction Nanopillars. PHYSICAL REVIEW LETTERS. 2011;107(17): 177201.We study tunneling magnetothermopower (TMTP) in CoFeB/MgO/CoFeB magnetic tunnel junction nanopillars. Thermal gradients across the junctions are generated by an electric heater line. Thermopower voltages up to a few tens of mu V between the top and bottom contact of the nanopillars are measured which scale linearly with the applied heating power and hence the thermal gradient. The thermopower signal varies by up to 10 mu V upon reversal of the relative magnetic configuration of the two CoFeB layers from parallel to antiparallel. This signal change corresponds to a large spin-dependent Seebeck coefficient of the order of 100 mu V/K and a large TMTP change of the tunnel junction of up to 90%
Toward Wafer Scale Inductive Characterization of Spin-Transfer Torque Critical Current Density of Magnetic Tunnel Junction Stacks
No full textWe explore the prospects of wafer-scale inductive probing of the critical current density j(c0) for spin-transfer torque (STT) switching of CoFeB/MgO/CoFeB magnetic tunnel junctions with varying MgO thickness. From inductive measurements, magnetostatic parameters and effective damping are derived and j(c0) is calculated based on STT equations. The inductive values compare well with the values derived from current-induced switching measurements on individual nanopillars. Using a wafer-scale inductive probe head could enable wafer probe station-based metrology of j(c0) in the future
Musical meaning and social significance : techno triggers for dancing
No full textElectronically-produced dance music has only recently achieved as much visibility in the
global pop music industry as ‘live’ or instrumental pop. Yet the fascination of cultural
scholars and sociologists with dance music predates its rise as a product of mass culture.
Much of this interest derives from early associations of dance music with marginalised
groups and oppositional ideologies. It therefore follows that many explorations of dance
music focus on the ways in which techno, house and practices of ‘raving’ are
expressions of dissent. As a result, the cultural aspects of dance music are necessarily the
focus of these studies, with few musicologists addressing musical features and fewer
dance scholars considering the specifics of dance movement. What is more, these
differing approaches tend to compete rather than collaborate. In my thesis, I seek to
address this divergence and to draw attention to the ways that contrasting disciplinary
approaches can complement and enrich the study of any music.
I use contemporary techno club nights in Edinburgh as a focal point for addressing
musical and social triggers for dancing. I explore subjective experiences of dancing,
DJing and producing by interspersing a review of existing literature with my own
ethnographic research and musical analysis. Subsequently, I consider how the
philosophies of techno are embodied within the movements and postures of the
dancing body and social interaction. Participants in techno settings adopt strikingly
similar attitudes to the institutionalised classical music world, despite the fundamental
differences between the practices of composition, performance and listening. Moreover,
these attitudes are repeatedly disseminated by participants, journalists and scholars. My
enquiry into social and musical dancing triggers leads me to question the perpetuation of
these ideas
RedDots: Limits on habitable and undetected planets orbiting nearby stars GJ 832, GJ 674, and Ross 128
No full textContext . The nearby ( d < 5 pc) M dwarfs GJ 832, GJ 674, and Ross 128 each host a single exoplanet, with Ross 128 b located within the optimistic habitable zone. Due to their low mass and close proximity, these three systems are prime candidates for further characterization studies. Aims . Using HARPS spectroscopic data obtained by the RedDots campaign, as well as archival data from HARPS and CARMENES, supplemented with ASH2 and T90 photometry, we aim to search for additional planets in the three systems. We also aim to determine limits on possible undetected, habitable planets. We investigate (i) the reliability of the recovered orbital eccentricities and (ii) the reliability of Bayesian evidence as a diagnostic for selecting the best model. Methods . We employed Markov-chain Monte Carlo, nested sampling, and Gaussian process (GP) analyses to fit a total of 20 different models comprising 0–2 Keplerian signals and three different GP kernels for stellar activity. We used the residuals to create grids for injection-recovery simulations to obtain detection limits on potentially undiscovered planets. Results . Our refined orbital elements for GJ 832 b, GJ 674 b, and Ross 128 b confirm (GJ 832, GJ 674) or increase (Ross 128) prior eccentricity determinations. No additional planets were found in any of the systems. The detection limits obtained for all three systems are between 30 and 50 cm s −1 for orbital periods in the range of 1–10 000 days. This corresponds to habitable planet masses of <1.5 M ⊕ for GJ 832 and < 1 M ⊕ for GJ 674 and Ross 128. Using N-body simulations, we find that undiscovered secondary planets are unlikely (Ross 128) or incapable (GJ 674) of having caused the observed eccentricities of the known planets. We find that the eccentricity of GJ 832b is not significantly different from zero. Conclusions . GJ 832 b, GJ 674 b, and Ross 128 b retain their status as hosting lonely and (for the latter two) eccentric planets ( e = 0.04, 0.24, 0.21; respectively). This is unexpected in classical planet formation scenarios, which favor circular orbits and multiplanet configurations, demonstrating that planet formation in these cases is more complicated than traditionally thought. Additionally, the eccentricity of Ross 128 indicates that it spends some of its orbit outside of the optimistic habitable zone. Finally, our results show that Bayesian evidence, when used in conjunction with GP, is not a robust diagnostic for selecting the best model in cases of low- activity stars. In such cases, we advise an inspection of the shapes of the posterior distributions and to ensure that relevant simulations are performed to assess the validity of the perceived best model
Magnetothermoelectric figure of merit of Co/Cu multilayers
No full textHu XK, Krzysteczko P, Liebing N, et al. Magnetothermoelectric figure of merit of Co/Cu multilayers. Applied Physics Letters. 2014;104(9): 092411.The switching of the magnetic configuration of giant magnetoresistance multilayers not only changes the electrical and thermal conductivities but also the thermopower. We study the magnetotransport and the magnetothermoelectric properties of Co/Cu multilayer devices in a lateral thermal gradient. The Seebeck coefficient reaches values up to -18 mu V/K at room temperature and shows a magnetic field dependence up to 28.6% upon spin reversal. In combination with thermal conductivity data of the same Co/Cu stack, we find a magnetothermoelectric figure of merit of up to 65%. Furthermore, a magneto-power factor of up to 110% is derived. (C) 2014 AIP Publishing LLC
Effect of molecular and electronic geometries on the electronic density in FLO-SIC
No full textRecently, Trepte et al. [J. Chem. Phys., vol. 155, 2021] pointed out the importance of analyzing dipole moments in the Fermi-Löwdin orbital (FLO) self-interaction correction (SIC) for cyclic, planar molecules. In this manuscript, the effect of the molecular and electronic geometries on dipole moments and polarizabilities is discussed for non-cyclic molecules. Computed values are presented for water, formaldehyde, and nitromethane. Continuing the work of Schwalbe et al. [J. Chem. Phys. vol. 153, (2020)], we reconfirm that systematic numerical parameter studies are essential to obtain consistent results in density functional theory (DFT) and SIC. In agreement with Trepte et al. [J. Chem. Phys., vol. 155, 2021], DFT agrees well with experiment for dipole moments, while SIC slightly overestimates them. A Linnett double-quartet electronic geometry is found to be energetically preferred for nitromethane.22 pages, 8 figures, 5 table
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