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991.
Komatsu K L'Hôte D Nakamae S Mosser V Konczykowski M Dubois E Dupuis V Perzynski R 《Physical review letters》2011,106(15):150603
We present the experimental observation of the fluctuation-dissipation theorem violation in an assembly of interacting magnetic nanoparticles in the low temperature superspin-glass phase. The magnetic noise is measured with a two-dimension electron gas Hall probe and compared to the out of phase ac susceptibility of the same ferrofluid. For "intermediate" aging times of the order of 1 h, the ratio of the effective temperature T(eff) to the bath temperature T grows from 1 to 6.5 when T is lowered from T(g) to 0.3 T(g), regardless of the noise frequency. These values are comparable to those measured in an atomic spin glass as well as those calculated for a Heisenberg spin glass. 相似文献
992.
The spin-valve complex magnetoimpedance of symmetric ferromagnet-normal-metal-ferromagnet junctions is investigated within the drift-diffusion (standard) model of spin injection. The ac magnetoresistance-the real part difference of the impedances of the parallel and antiparallel magnetization configurations-exhibits an overall damped oscillatory behavior, as an interplay of the diffusion and spin relaxation times. In wide junctions the ac magnetoresistance oscillates between positive and negative values, reflecting resonant amplification and depletion of the spin accumulation, while the line shape for thin tunnel junctions is predicted to be purely Lorentzian. The ac spin-valve effect could be a technique to extract spin transport and spin relaxation parameters in the absence of a magnetic field and for a fixed sample size. 相似文献
993.
Novitsky DV 《Optics letters》2011,36(11):2002-2004
Fano mechanism is the universal explanation of asymmetric resonance appearing in different systems. We report the evidence of Fano-like resonance in selective reflection from a resonant two-level medium. We draw an analogy with the asymmetric resonance previously obtained for the coupled oscillators. We also take into account the effects of dielectric background and local-field correction and connect our results with optical bistability. 相似文献
994.
We report broadband transmissions of terahertz radiations through the air channel of thin-wall pipe. The impacts of the wall thickness and of the refractive index of the material on the transmission window bandwidth are investigated. An extension of the bandwidth by at least 5.5 times is reported with a commercial drinking straw. The salient properties of the antiresonant reflecting guiding mechanism are studied with the terahertz time domain spectroscopy method, including the reduction of the attenuation coefficient of the propagated field by 60 times the material absorption coefficient. 相似文献
995.
Lysova A. A. Marchenko R. D. Samsonenko D. G. Potapov A. S. Fedin V. P. 《Russian Chemical Bulletin》2020,69(6):1122-1129
Russian Chemical Bulletin - Four new metal-organic frameworks were synthesized based on the N-donor ligand 1,5-bis(3,5-dimethylpyrazol-1-yl)-3-selenapentane (L) novel in this field of chemistry:... 相似文献
996.
Denis S. Krylov Sebastian Schimmel Vasilii Dubrovin Fupin Liu T. T. Nhung Nguyen Lukas Spree Chia‐Hsiang Chen Georgios Velkos Claudiu Bulbucan Rasmus Westerstrm Micha Studniarek Jan Dreiser Christian Hess Bernd Büchner Stanislav M. Avdoshenko Alexey A. Popov 《Angewandte Chemie (International ed. in English)》2020,59(14):5756-5764
Magnetic hysteresis is demonstrated for monolayers of the single‐molecule magnet (SMM) Dy2ScN@C80 deposited on Au(111), Ag(100), and MgO|Ag(100) surfaces by vacuum sublimation. The topography and electronic structure of Dy2ScN@C80 adsorbed on Au(111) were studied by STM. X‐ray magnetic CD studies show that the Dy2ScN@C80 monolayers exhibit similarly broad magnetic hysteresis independent on the substrate used, but the orientation of the Dy2ScN cluster depends strongly on the surface. DFT calculations show that the extent of the electronic interaction of the fullerene molecules with the surface is increasing dramatically from MgO to Au(111) and Ag(100). However, the charge redistribution at the fullerene‐surface interface is fully absorbed by the carbon cage, leaving the state of the endohedral cluster intact. This Faraday cage effect of the fullerene preserves the magnetic bistability of fullerene‐SMMs on conducting substrates and facilitates their application in molecular spintronics. 相似文献
997.
Talina R. Rusch Alexander Schlimm Nicolai R. Krekiehn Tobias Tellkamp imon Budzk Denis Jacquemin Felix Tuczek Rainer Herges Olaf M. Magnussen 《Angewandte Chemie (International ed. in English)》2020,59(39):17192-17196
Light‐induced transitions between the trans and cis isomer of triazatriangulenium‐based azobenzene derivatives on Au(111) surfaces were observed directly by scanning tunneling microscopy, allowing atomic‐scale studies of the photoisomerization kinetics. Although the azobenzene units in these adlayers are free‐standing and spaced at uniform distances of 1.26 nm, their photoswitching depends on the isomeric state of the surrounding molecules and, specifically, is accelerated by neighboring cis isomers. These collective effects are supported by ab initio calculations indicating that the electronic excitation preferably localizes on the n–π* state of trans isomers with neighboring cis azobenzenes. 相似文献
998.
Bastien Néel Majid Ghahraman Asfhar Gastón A. Crespo Marcin Pawlak Denis Dorokhin Eric Bakker 《Electroanalysis》2014,26(3):473-480
A series of polymeric nitrite‐selective electrodes containing a new lipophilic ionophore Co(II) tert‐butyl‐salophen is reported. The stability of Co(II) ionophores within a PVC‐based membrane was investigated by leaching experiments. Different membrane compositions were explored in order to reach the lowest possible limit of detection for a PVC‐based nitrite selective polymeric membrane electrode containing this ionophore. The optimal electrode showed a limit of detection of 2×10?6 M and exhibited four orders of magnitude of discrimination over nitrate, chloride and bromide. The electrodes were evaluated in undiluted human urine and attest to the robustness of the ionophore. 相似文献
999.
Dr. Denis Lesage Prof. Anne Milet Dr. Antony Memboeuf Jérôme Blu Dr. Andrew E. Greene Prof. Jean‐Claude Tabet Dr. Yves Gimbert 《Angewandte Chemie (International ed. in English)》2014,53(7):1939-1942
The mechanism of the Pauson–Khand reaction has been studied by mass spectrometry and it has been found, through ion‐molecule reaction with 13CO, that the carbon monoxide incorporated into the product cyclopentenone is one that has been retained within the complex. Theoretical and kinetic calculations support this finding, which provides a complementary explanation for the effect of Pauson–Khand promoters. 相似文献
1000.
Dr. Fabio Denis Romero Alice Leach Dr. Johannes S. Möller Francesca Foronda Prof. Stephen J. Blundell Prof. Michael A. Hayward 《Angewandte Chemie (International ed. in English)》2014,53(29):7556-7559
A series of strontium vanadium oxide–hydride phases prepared by utilizing a low‐temperature synthesis strategy in which oxide ions in Srn+1VnO3n+1 (n=∞, 1, 2) phases are topochemically replaced by hydride ions to form SrVO2H, Sr2VO3H, and Sr3V2O5H2, respectively. These new phases contain sheets or chains of apex‐linked V3+O4 squares stacked with SrH layers/chains, such that the n=∞ member, SrVO2H, can be considered to be analogous to “infinite‐layer” phases, such as Sr1?xCaxCuO2 (the parent phase of the high‐Tc cuprate superconductors), but with a d2 electron count. All three oxide–hydride phases exhibit strong antiferromagnetic coupling, with SrVO2H exhibiting an antiferromagnetic ordering temperature, TN>300 K. The strong antiferromagnetic couplings are surprising given they appear to arise from π‐type magnetic exchange. 相似文献