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H. Chibani J.P. Stoquert M. Hage-Ali J.M. Koebel M. Abdesselam P. Siffert 《Applied Surface Science》1991,50(1-4):177-180
We describe the capabilities of the nuclear reaction
the measurement of absolute concentrations of C in CdTe by the charged particle activation (CPA) method. This technique is used to determine the segregation coefficient of C introduced as an impurity in CdTe. 相似文献
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Andrade LH Laraoui A Vomir M Muller D Stoquert JP Estournès C Beaurepaire E Bigot JY 《Physical review letters》2006,97(12):127401
The ultrafast magnetization and electron dynamics of superparamagnetic cobalt nanoparticles, embedded in a dielectric matrix, have been investigated using femtosecond optical pulses. Our experimental approach allows us to bypass the superparamagnetic thermal fluctuations and to observe the trajectory of the magnetization vector which exhibits a strongly damped precession motion. The magnetization precession is damped faster in the superparamagnetic particles than in cobalt films or when the particle size decreases, suggesting that the damping is enhanced at the metal dielectric interface. Our observations question the gyroscopic nature of the magnetization pathway when superparamagnetic fluctuations take place as we discuss in the context of Brown's model. 相似文献
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Spectroscopic ellipsometry is used to investigate optical properties of cobalt-implanted silica thin films. The films under investigation are 250 nm thick thermal SiO2 layers on Si substrates implanted with Co+ ions at energy of 160 keV and at fluences of 1017 ions/cm2 for different temperatures of substrate during implantation (77 and 295 K). Changes due to Co+ implantation are clearly observed in the optical response of the films. Optical behaviours are furthermore different for the three implantation temperatures. To understand the optical responses of these layers, the ellipsometric experimental data are compared to different models including interference effects and metal inclusions effects into the dielectric layer. The simulated ellipsometric data are obtained by calculating the interferences of an inhomogeneous layer on a Si substrate. The material within this layer is considered as an effective medium which dielectric function is calculated using the Maxwell-Garnett effective medium approximation. We show that although the structures of these layers are very complicated because of ion-implantation mechanisms, quite simple models can provide relatively good agreement. The possibilities of ellipsometry for the study of the optical properties of such clusters-embedded films are discussed. We especially provide the evidence that ellipsometry can give interesting information about the optical properties of nanostructured layers. This is of special interest in the field of nanostructured layered systems where ellipsometry appears to be a suitable optical characterization technique. 相似文献
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The structural and electronic transport properties of La1−x
Ce
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MnO3 (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with
Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration
up to 50% doping. The system La0.5Ce0.5MnO3 also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition. 相似文献
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