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61.
C.?Gatel E.?SnoeckEmail author V.?Serin A. R.?Fert 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,45(2):157-168
Epitaxial Fe3O4/NiO bilayers were epitaxially grown on MgO(001)
and Al2O3(0001) substrates to investigate the influence of the
fully spin compensated (001) and the non-compensated (111) NiO interface
planes between the ferromagnetic (F) and antiferromagnetic (AF) layers on
the AF/F exchange coupling. Bilayers of different magnetite thicknesses and
constant NiO thickness were investigated. The structural characterizations
indicate a perfect epitaxy of the two layers for the both growth directions
in the two Fe3O4/NiO/MgO(001) and
NiO/Fe3O4/Al2O3(0001) systems. An epitaxial
ferrimagnetic (Ni,Fe)Fe2O4 phase is observed at the AF/F
interface when the NiO oxide is grown on the top of the Fe3O4
layer while a perfectly flat AF/F interface is observed in the
Fe3O4/NiO/MgO(001) system exhibiting only a very slight
interdiffusion. Magnetic measurements indicate a relative strong bias at
300 K for the bilayers grown on Al2O3(0001), which decreases with
the inverse of the ferrimagnetic layer thickness as theoretically expected.
On the contrary, a zero exchange biasing is observed at 300 K for the
bilayers grown on MgO(001). 相似文献
62.
Independent currents at right angles were sent through type II superconducting alumnum films in the flux-flow state, and the voltage measured along one of the current directions. The voltage was found to increase with increasing perpendicular current, due to the non-linear voltage characteristics of the specimens. 相似文献
63.
A new series of macrocyclic imine-oxime complexes prepared by template condensation of o-phenylenediamine, phthaldialdehyde, 2,6-diacetylpyridine and dichloroglyoxime in MeOH solution, have been characterized by i.r., electronic spectral data, elemental analyses, conductivity and magnetic susceptibility measurements. In the imine moiety of the complexes, the chloride ions coordinate to the nickel ion. From conductivity measurements, it was shown that the complexes are not all electrolytes. Their thermal behaviour has been studied by the t.g. and d.t.a. analysis. They decompose with loss of the organic ligand and halogen to leave the metal oxide. 相似文献
64.
Bregiroux D Terra O Audubert F Dacheux N Serin V Podor R Bernache-Assollant D 《Inorganic chemistry》2007,46(24):10372-10382
On the basis of optimized grinding/heating cycles developed for several phosphate-based ceramics, the preparation of brabantite and then monazite/brabantite solid solutions loaded with tetravalent thorium, uranium, and cerium (as a plutonium surrogate) was examined versus the heating temperature. The chemical reactions and transformations occurring when heating the initial mixtures of AnO2/CeO2, CaHPO(4).2H2O (or CaO), and NH4H2PO4 were identified through X-ray diffraction (XRD) and thermogravimetric/differential thermal analysis experiments. The incorporation of thorium, which presents only one stabilized oxidation state, occurs at 1100 degrees C. At this temperature, all the thorium-brabantite samples appear to be pure and single phase as suggested by XRD, electron probe microanalyses, and micro-Raman spectroscopy. By the same method, tetravalent uranium can be also stabilized in uranium-brabantite, i.e., Ca0.5U0.5PO4, after heating at 1200 degrees C. Both brabantites, Ca0.5Th0.5PO4 and Ca0.5U0.5PO4, begin to decompose when increasing the temperature to 1400 and 1300 degrees C, respectively, leading to a mixture of CaO and AnO2 by the volatilization of P4O10. In contrast to the cases of thorium and uranium, cerium(IV) is not stabilized during the heating treatment at high temperature. Indeed, the formation of Ca0.5Ce0.5PO4 appears impossible, due to the partial reduction of cerium(IV) into cerium(III) above 840 degrees C. Consequently, the systems always appear polyphase, with compositions of CeIII1-2xCeIVxCaxPO4 and Ca2P2O7. The same conclusion can be also given when discussing the incorporation of cerium(IV) into La1-2xCeIIIx-yCeIVyCay(PO4)1-x+y. This incomplete incorporation of cerium(IV) confirms the results obtained when trying to stabilize tetravalent plutonium in Ca0.5PuIV0.5PO4 samples. 相似文献
65.
The energy distribution profile of the interface states (Nss) of Al/TiO2/p-Si (MIS) structures prepared using the sol-gel method was obtained from the forward bias current-voltage (I-V) characteristics by taking into account both the bias dependence of the effective barrier height (?e) and series resistance (Rs) at room temperature. The main electrical parameters of the MIS structure such as ideality factor (n), zero-bias barrier height (?b0) and average series resistance values were found to be 1.69, 0.519 eV and 659 Ω, respectively. This high value of n was attributed to the presence of an interfacial insulator layer at the Al/p-Si interface and the density of interface states (Nss) localized at the Si/TiO2 interface. The values of Nss localized at the Si/TiO2 interface were found with and without the Rs at 0.25-Ev in the range between 8.4×1013 and 4.9×1013 eV−1 cm−2. In addition, the frequency dependence of capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics of the structures have been investigated by taking into account the effect of Nss and Rs at room temperature. It can be found out that the measured C and G/ω are strongly dependent on bias voltage and frequency. 相似文献
66.
New immobilized Schiff bases 总被引:1,自引:1,他引:0
In this study, three new immobilized Schiff bases and their Co(II), Cu(II) and Ni(II) metal complexes have been prepared.
The ligands silica-Si[N-(3-propyl)2,4-dihydroxybenzaldimine] (1) H2L, silica-Si[N-(3-propyl)4-methylsalicylaldimine-3-methoxy] (2) HL and silica-Si[N-(3-propyl)2-pyridinecarboxyaldimine] (3)
L have bidentate characters. Therefore, the complexes are the mononuclear. Ligands and metal complexes were characterized
by FTIR, AAS and thermoanalytical techniques. On the basis of analytical data and IR studies, a 1:1 metal to ligand stoichiometry
has been suggested. TG and DTA results showed that these ligands and complexes had good thermal stability. The heat capacities
of ligands were reported in the temperature range 273–363 K as no thermal anomaly was found in this temperature range. 相似文献
67.
Oztekin Algul Asiye Meric Serpil Polat N. Didem Yuksek Mehmet S. Serin 《Central European Journal of Chemistry》2009,7(3):337-342
Comparative studies were performed on a series of 2,4-di and 2,3,4-trisubstituted benzimidazo[1,2-a]pyrimidines, which were
synthesized with conventional and microwave heating methods. In microwave irradiation method, approximately, 95–97.5% of the
reaction time was increased and 1–45% yield increase was obtained. All compounds were able to inhibit the growth of the screened
microorganisms in vitro with MIC values between 3.9–250 μg mL−1. The highest activity was expressed by compound IIId (2,4-diphenyl-benzo[4,5]imidazo[1,2-a] pyrimidine), which has the MIC
value of 3.9 μg mL−1 and 31.2 μg mL-1 for Penicillium natatum ATCC 24791 and E. faecalis ATCC 29212, respectively.
相似文献
68.
Electrical transport properties in CuO thin films processed using d.c. magnetron sputtering technique is investigated to understand the correlation between the processing conditions and electrical properties. It is identified that the temperature dependent conductivity of the investigated films is controlled by the multi-phonon hopping conduction mechanism. A detailed analysis in terms of carrier hopping parameters is used to correlate electrical transport properties with the d.c. magnetron sputtering conditions. 相似文献
69.
Temperature-dependent conductivity and thermopower measurements are carried out for undoped and In-doped CuO thin films. We investigate the effects of In-doping on carrier transport properties of CuO thin films in the temperature range of 300?<?T?<?400?K. Carrier transport is dominated by simple thermally activated conduction in the undoped film. On the other hand, small polarons play an essential role in the carrier transport properties in the In-doped films. By increasing the In content, the conduction behaviour transits from adiabatic limit to the non-adiabatic limit, and the conductivity decreases. 相似文献