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Novel spin glasses by mechanical milling

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Science China(Technological Sciences) 1996年第4期39卷 354-368页

作者：周国富 H.Bakker van der waals-zeeman Laboratorium Universiteit van AmsterdamValckenierstraat 65.1018 XE Amsterdam.Netherlands Present address: Philips Research Laboratories. Prof Holstlaan 4. 5656 AA Eindhoventhe Netherlands. van der waals-zeeman Laboratorium Universiteit van AmsterdamValckenierstraat 65.1018 XE Amsterdam.Netherlands

Novel spin-glass alloys were synthesized by milling intermetallic compounds and also by milling mixtures of crystalline elemental powder in a high-energy ball *** glass behaviour was found in amorphous Co2Ge,which was amorphised by milling in mechanically disordered crystalline GdAl2 in ball-milled crystalline and amorphous CoZr,and in mechanically alloyed Co-Cu,which formed a supersaturated *** *** these materials are binary alloys and tlie concentration of the magnetic element is high,which makes them novel types of spin *** is shown that ball milling may not only lead to structural metallic glasses,but can also generate the magnetic pendant of a structural glass,namely the spin glass.

关键词： spin glasses disorder phase transformation ball milling intermetallic compounds.

Structural and Magnetic Properties of Tb(Fe_(1-x)Ni_(x))_(11.3)Nb_(0.7) Compounds

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Chinese Physics Letters 1998年第12期15卷 922-924页

作者： WANG Jian-li YANG Fu-ming BAO Fu-quan TANG Ning HAN Xiu-feng YANG Dong ZHANG Cheng F.Rde Boer State Key Laboratory of Magnetism Institute of PhysicsChinese Academy of SciencesBeijing 100080 van der waals-zeeman institute University of AmsterdamValckenierstraat 651018 XE AmsterdamThe Netherlands

Structural and magnetic properties of Tb(Fe_(1-x)Ni_(x))_(11.3)Nb_(0.7) compounds have been *** x-ray diffraction patterns show that all compounds crystallize in the ThMn12-type structure and that all samples are almost of single *** lattice constants monotonously decrease with increasing Ni *** Curie temperature Tc clearly increases and the saturation moment Ms monotonously decreases with increasing Ni content.X-ray diffraction patterns of aligned samples at room temperature show that for x≤0.2 the easy magnetization direction is in the plane while for the x=0.25 compound the easy magnetization direction is along the *** the compounds with x≤0.20 spin reorientation occurs above room temperature whereas in the compounds with x>0.2 there is a spin reorientation below room *** has been found that Ni contributes positively to the T-sublattice moment MT.

关键词： temperature. compounds magnetization

Magnetocaloric effects in Fe_4MnSi_3B_x interstitial compounds

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Acta Metallurgica Sinica(English Letters) 2009年第5期22卷 397-400页

作者： Yongli WU O. Tegus Weiguang ZHANG S. Yiriyoltu B. Mend Songlin Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials Inner Mongolia Normal University Huhhot 010022 China van der waals-zeeman Instituut Universiteit van Amsterdam Valckenierstraat 65 1018 XE Amsterdam The Netherlands

The magnetic properties and magnetocaloric effect in Fe4MnSi3B~ compounds with x=0, 0.05, 0.10, 0.15, 0.20, 0.25 have been investigated. X-ray diffraction study shows that all these compounds investigated crystallize in the MnsSi3-type structure with space group P63/mcm. Boron insertion in the host ternary silicide Fe4MnSi3 does not change the crystal symmetry, only leads to an increase of the lattice parameters, indicating the B atoms entered the interstitial sites. With increasing B content, the Curie temperature shifts to higher temperatures. The maximal magnetic-entropy changes of the Fe4MnSi3Bx compounds with x=0, 0.10 and 0.20 are about 1.8 J/（kg.K）, 1.8 J/（kg-K） and 1.6 J/（kg.K）, respectively, for a field change from 0 to 1.5 T.

关键词： Transition metal interstitial compounds Magaetocatoric effect Magnetic properties

Carrier multiplication in germanium nanocrystals

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Light(Science & Applications) 2015年第1期4卷 498-503页

作者： Saba Saeed Chris de Weerd Peter Stallinga Frank CM Spoor Arjan J Houtepen Laurens DA Siebbeles Tom Gregorkiewicz van der waals-zeeman institute University of Amsterdam1098 XH AmsterdamThe Netherlands FCT-DEEI University of the Algarve8005-139 FaroPortugal Optoelectronic Materials Faculty of Applied SciencesDelft University of Technology2628 BL DelftThe Netherlands

Carrier multiplication is demonstrated in a solid-state dispersion of germanium nanocrystals in a silicon–dioxide *** is performed by comparing ultrafast photo-induced absorption transients at different pump photon energies below and above the threshold energy for this *** average germanium nanocrystal size is approximately 5–6 nm,as inferred from photoluminescence and Raman spectra.A carrier multiplication efficiency of approximately 190%is measured for photo-excitation at 2.8 times the optical bandgap of germanium nanocrystals,deduced from their photoluminescence spectra.

关键词： carrier multiplication germanium nanocrystals transient absorption

Electrochemically-stimulated nanoscale mechanochemical wear of silicon

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Friction 2023年第11期11卷 2142-2152页

作者： Chen XIAO Stefan van VLIET Roland BLIEM Bart WEBER Steve FRANKLIN Advanced Research Center for Nanolithography(ARCNL) Amsterdam 1098XGthe Netherlands van der waals–zeeman institute Institute of PhysicsUniversity of Amsterdam(UvA)Amsterdam 1098XGthe Netherlands Department of Materials Science and Engineering The University of SheffieldSheffield S13JDUK

Mechanochemical reactions at the sliding interface between a single-crystalline silicon(Si)wafer and a silica(SiO2)microsphere were studied in three environmental conditions:humid air,potassium chloride(KCl)solution,and KCl solution with an applied *** to that from humid air,mechanochemical material removal from the silicon surface increased substantially in the KCl-immersed condition,and further increased when electrochemistry was introduced into the tribological *** measuring the load dependence of the material removal rate and analyzing the results using a mechanically assisted Arrhenius-type kinetic model,the activation energy(E_(a))and the mechanical energy(E_(m)),by which this energy is reduced by mechanical activation,were compared qualitatively under different environmental *** the KCl-immersed condition,mechanochemistry may decrease the required effective energy of reactions(E_(eff)=E_(a)−E_(m))and promote material removal mainly through improved catalysis of the mechanochemical reactions facilitated by greater availability of water molecules compared to the humid air ***,the effectiveness of the mechanochemistry is *** the electrochemical condition,electrochemically-accelerated oxidation of the silicon surface was confirmed by the X-ray photoelectron spectroscopy(XPS)*** results strongly suggest that electrochemistry further stimulates mechanochemical reactions primarily by increasing the initial energy state of the surface via the facilitated formation of interfacial bonding bridges,i.e.,a surface oxidation/hydroxylation process.

关键词： spherical contact adhesive wear normal loading power law

Magnetic properties of Fe_(3(1-x))Cr_(3x)C alloys

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International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 314-316页

作者： Feng-qi Zhao O. Tegus B. Fuquan E. Brück Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials College of Physics and Electron Information Inner Mongolia Normal University Hohhot 010022 China van der waals-zeeman Instituut Universiteit van Amsterdam Valckenierstraat 65 1018XE Amsterdam Netherlands

The magnetic properties of Fe3（1-x）Cr3xC alloys with x=0.05, 0.1, 0.15, and 0.2, which crystallize in the cementite Fe3C-type structure with space group Pnma, were investigated by means of magnetization measurements. These alloys show temperature-induced second-order magnetic phase transitions. The Curie temperature （Tc） of these alloys decreases with increasing x. The isothermal magnetic-entropy changes of these alloys were derived from the magnetic isotherms measured with increasing temperature and increasing field. The maximum values of the magnetic-entropy change are about 0.9 and 3.6 J·kg^-1·K^-1 at Tc =360 K for x = 0.05 in a magnetic field change from 0 to 1 T and 0 to 5 T, respectively.

关键词： magnetic properties magnetocaloric effect magnetic-entropy change magnetic refrigeration

Cooperative interactions between nano-antennas in a high-Q cavity for unidirectional light sources

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Light(Science & Applications) 2019年第1期8卷 82-95页

作者： Kevin G.Cognee Hugo M.Doeleman Philippe Lalanne A.F.Koenderink Center for Nanophotonics AMOLFScience Park 1041098 XG AmsterdamThe Netherlands LP2N Institut d’Optique Graduate SchoolCNRSUniversity of Bordeaux33400 TalenceFrance van der waals-zeeman institute University of AmsterdamScience Park 9041090 GL AmsterdamThe Netherlands

We analyse the resonant mode structure and local density of states in high-Q hybrid plasmonic-photonic resonators composed of dielectric microdisks hybridized with pairs of plasmon antennas that are systematically swept in position through the cavity *** the one hand,this system is a classical realization of the cooperative resonant dipole–dipole interaction through a cavity mode,as is evident through predicted and measured resonance linewidths and *** the same time,our work introduces the notion of‘phased array’antenna physics into plasmonic-photonic *** predict that one may construct large local density of states(LDOS)enhancements exceeding those given by a single antenna,which are‘chiral’in the sense of correlating with the unidirectional injection of fluorescence into the *** report an experiment probing the resonances of silicon nitride microdisks decorated with aluminium antenna *** directly confirm the predicted cooperative effects of the coupled dipole antennas as a function of the antenna spacing on the hybrid mode quality factors and resonance conditions.

关键词： antenna antennas cavity

CALCULATION OF THE MAGNETIZATION AND MAGNETOCALORIC EFFECT IN THE MnFeP_(0.45)As_(0.55) COMPOUND

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 265-269页

作者： G.F. Wang L. Song Z.Q. Ou Z.R. Zhao O. Tegus Key Laboratory of Physics and Chemistry of Function Materials Inner Mongolia Normal University Huhhot 010022 China van der waals-zeeman Instituut Universiteit van Amsterdam Valckenierstraat 65 1018 XE Amsterdam The Netherlands College of Science and Technology Inner Mongolia University Huhhot 010021 China

A magnetic state equation of the MnFeP0.45As0.55 compound has been obtained by minimizing the Gibbs free energy with respect to the volume and the magnetization based on the Bean-Rodbell model. The isothermal magnetization of the compound has been calculated using this equation. The magnetic entropy change of the compound was determined from the surface area between the two adjacent isothermal magnetization curves divided by the average temperature. A comparison and an error analysis of the calculated magnetic entropy change and the one determined from the experimental data were given.

关键词： bean-rodbell model magnetic state equation magnetocaloric effect

Neuronal photoactivation through secondharmonic near-infrared absorption by gold nanoparticles

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Light(Science & Applications) 2018年第1期7卷 79-91页

作者： Wieteke D.A.M.de Boer Jan J.Hirtz Antonio Capretti Tom Gregorkiewicz Mercè Izquierdo-Serra Shuting Han Christophe Dupre Yuriy Shymkiv Rafael Yuste NeuroTechnology Center Department of Biological SciencesColumbia UniversityNew YorkNY 10027USA van der waals–zeeman institute University of Amsterdam1098 XH AmsterdamNetherlands Present address:Laboratori de Fisiologia Molecular Departament de Ciències Experimentals i de la SalutUniversitat Pompeu FabraBarcelonaSpain

Optical activation of neurons requires genetic manipulation or the use of chemical photoactivators with undesirable side *** a solution to these disadvantages,here,we demonstrate optically evoked neuronal activity in mouse cortical neurons in acute slices and in vivo by nonlinear excitation of gold *** addition,we use this approach to stimulate individual epitheliomuscular cells and evoke body contractions in Hydra *** achieve this,we use a low-power pulsed near-infrared excitation at the double-wavelength of the plasmon resonance of gold nanoparticles,which enables optical sectioning and allows for high spatial precision and large penetration *** effect is explained by second-harmonic Mie scattering,demonstrating light absorption by a second-order nonlinear process,which enables photothermal stimulation of the *** approach also minimizes photodamage,demonstrating a major advancement towards precise and harmless photoactivation for neuroscience and human therapeutics.

关键词： activation harmonic absorption