The variations of magnetization and magneto- striction with temperature and stress were investigated through the analysis of the effective field, induced by temperature and stress. A nonlinear magnetostrictive model o...The variations of magnetization and magneto- striction with temperature and stress were investigated through the analysis of the effective field, induced by temperature and stress. A nonlinear magnetostrictive model of giant magnetostrictive materials was proposed. The proposed model can be used to calculate the magnetostrictive characterization of giant magnetostrictive materi- als in different temperatures and under different stresses. The coupling effects of axial stress, magnetic field, and temperature on the magnetostriction of a Terfenol-D rod were numerically simulated as well as experimentally tested. Comparison between the calculating and experimental results shows that the proposed model can better describe the magneto-thermo-mechanical characteristics of Terfenol-D rod under different temperatures and compressive stress. Therefore, the proposed model possesses an important significance for the design of magnetostrictive devices.展开更多
The quantitative analysis of zinc isopropyl-isooctyl-dithiophosphate (T204) mixed with lube base oil from Korea with viscosity index 70 (T204-Korea70) is presented by using terahertz time-domain spectroscopy (THz-TDS)...The quantitative analysis of zinc isopropyl-isooctyl-dithiophosphate (T204) mixed with lube base oil from Korea with viscosity index 70 (T204-Korea70) is presented by using terahertz time-domain spectroscopy (THz-TDS).Compared with the middle-infrared spectra of zinc n-butyl-isooctyl-dithiophosphate (T202) and T204,THz spectra of T202 and T204 show the weak broad absorption bands.Then,the absorption coefficients of the T204-Korea70 system follow Beer's law at the concentration from 0.124 to 4.024%.The experimental absorption spectra of T204-Korea70 agree with the calculated ones based on the standard absorption coefficients of T204 and Korea70.The quantitative analysis enables a strategy to monitor the formulation of lubricating oil in real time.展开更多
An Ni-AI-Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3A1) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, A1...An Ni-AI-Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3A1) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, A1) random solid solutions are calculated as a function of the concentrations of Co and A1. The calculated SFEs decrease with increasing concentrations of Co and A1, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni(Co) solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ(Ni) may be improved by the addition of Co.展开更多
We study theoretically the electronic and transport property for an armchair-edge graphene nanoribbon (GNR.) with 12 and 11 transversal atomic lines, respectively. The ONR. is irradiated under an external longitudin...We study theoretically the electronic and transport property for an armchair-edge graphene nanoribbon (GNR.) with 12 and 11 transversal atomic lines, respectively. The ONR. is irradiated under an external longitudinal polarized high-frequency electromagnetic field at low temperatures. Within the framework of linear response theory in the perturbative regime, we examine the joint density of states and the real conductance of the system. It is demonstrated that, by numerical examples, some new photon-assisted intersubband transitions over a certain range of field frequency exist with different selection rules from those of both zigzag-edge GNR. and single-walled carbon nanotube. This opto-electron property dependence of armchair-edge GNR. on field frequency may be used to detect the high-frequency electromagnetic irradiation.展开更多
This paper investigates theoretically the electronic structure and transport of a two-level quantum dot irradiated under a strong laser field at low temperatures. Using the method of Keldysh equation of motion for non...This paper investigates theoretically the electronic structure and transport of a two-level quantum dot irradiated under a strong laser field at low temperatures. Using the method of Keldysh equation of motion for nonequilibrium Green functions, it examines the time-averaged density of states and conductance for the system with photon polarization parallel with and perpendicular to the tunnelling current direction respectively. It is demonstrated that, by analysing some numerical examples, more photon sidebands resonance states and multi-and single-photon transitions are found when diagonal matrix elements dominate the interaction, while the electronic transitions due to multiphoton absorption are more or less suppressed when off-diagonal interaction dominates.展开更多
We investigate theoretically the electron transport of a two-level quantum dot irradiated under a weak laser field at low temperatures in the rotating wave approximation. Using the method of the Keldysh equation of mo...We investigate theoretically the electron transport of a two-level quantum dot irradiated under a weak laser field at low temperatures in the rotating wave approximation. Using the method of the Keldysh equation of motion for nonequilibrium Green function, we examine the conductance for the system with photon polarization perpendicular to the tunnelling current direction. It is demonstrated that by analytic analysing and numerical examples, a feature of conductance peak splitting appears, and the dependence of conductance on the incident laser frequency and self-energy are discussed.展开更多
A new class of 1D quasiperiodic lattices,for which the substitution rules are B→BA,and A→BAB,has been studied in several aspects.The high-dimensional projection method for obtaining the quasilattice is presented.A m...A new class of 1D quasiperiodic lattices,for which the substitution rules are B→BA,and A→BAB,has been studied in several aspects.The high-dimensional projection method for obtaining the quasilattice is presented.A multifractral spectral behavior and gap fabeling properties have been found,which display the perfect quasiperiodicity of the studied model.展开更多
By using the Hardy-Wright-Mobius inverse formula,we have improved the Carlsson-Gelatt-Ehrenreich scheme for the inverse problem of cohesive energy.The advantage of the new method is that the inverse formula are in a s...By using the Hardy-Wright-Mobius inverse formula,we have improved the Carlsson-Gelatt-Ehrenreich scheme for the inverse problem of cohesive energy.The advantage of the new method is that the inverse formula are in a sense independent of the geometries of lattices.展开更多
We theoretically study the low temperature electron transport properties of a weak Rashba spin-orbit coupling (SOC) semiconductor quantum wire connected nonadiabatically to two electrode leads without SOC. The wire ...We theoretically study the low temperature electron transport properties of a weak Rashba spin-orbit coupling (SOC) semiconductor quantum wire connected nonadiabatically to two electrode leads without SOC. The wire and the leads are defined by a parabolic confining potential, and the influence of both the wire-lead connection and the Rashba SOC on the electron transport is treated analytically by means of scattering matrix within effective free-electron approximation. From analytical analysis and numerical examples, we find that the system shows some fractional quantum conductance behaviour, and for some particular wire width a pure spin polarized current exists. Our result may imply a simple method for the design of a spin filter without involving any magnetic materials or magnetic fields.展开更多
ZrSiO4 and coesite were obtained under high-pressure and high-temperature from the nano precursor of a-SiO2 and ZrO2. XRD and Raman measurements indicate that ZrSiO4 was formed at a temperature higher than 920 ℃ unde...ZrSiO4 and coesite were obtained under high-pressure and high-temperature from the nano precursor of a-SiO2 and ZrO2. XRD and Raman measurements indicate that ZrSiO4 was formed at a temperature higher than 920 ℃ under a pressure of 3.6 GPa. As the pressure increased to 3.9 GPa, the ZrSiO4 formation temperature was reduced to 815 ℃. The formation temperature for coesite was 990 ℃ under 3.9 GPa. The lower formation temperature for ZrSiO4, as compared to that for coesite, provided an experimental evidence that the coesite in the Earth's surface usually occurs as inclusions in ZrSiO4.展开更多
We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependentrotating magnetic field.Based on the algebraic structure of the non-autonomous system,the exact solution of theSchrdinger ...We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependentrotating magnetic field.Based on the algebraic structure of the non-autonomous system,the exact solution of theSchrdinger equation is obtained by using the method of algebraic dynamics.Based on the time-dependent analyticalsolution,we further study the entanglement evolution between the two coupled spins for different initial states,and findthat the entanglement is determined by the coefficients of the initial state and the coupling constant J of the system.展开更多
We examine RCoO3 (R=La, Ce, Pr, Nd, Sin, Eu, Gd, and Dy) perovskites prepared with the solid-state reaction method by Raman spectroscopy, and report the Raman active phonons in the RCoO3 perovskites crystallized in ...We examine RCoO3 (R=La, Ce, Pr, Nd, Sin, Eu, Gd, and Dy) perovskites prepared with the solid-state reaction method by Raman spectroscopy, and report the Raman active phonons in the RCoO3 perovskites crystallized in cubic symmetry for RCoO3 (R=La, Ce, Pr and Nd) and orthorhombic symmetry for RCoO3 (R=Sm, Eu, Gd, and Dy). It is found that the Raman spectra of RCoO3 perovskites are strongly dependent on the ionic radius of the rare earth elements, and the frequency shift of the most intense modes of the orthorhombic samples are correlated with some structural parameters such as Co-O bond distances, ionic radius of the rare earth elements and Jahn-Teller distortion. It is clear that Raman spectroscopy has the advantage of sensitivity to structure distortion and oxygen motion.展开更多
TixAl1-xN films have been prepared by RF reactive magnetron sputtering. X-ray diffraction results showed that TixAl1-xN thin films in this study were hexagonal wurtzite structure with the Ti content up to 0.18. X-ray ...TixAl1-xN films have been prepared by RF reactive magnetron sputtering. X-ray diffraction results showed that TixAl1-xN thin films in this study were hexagonal wurtzite structure with the Ti content up to 0.18. X-ray photoelectron spectrocopy studies provided that the Nls core-electron spectrum of TixAl1-xN thin film brodend with increasing Ti content, and the difference of the chemical shifts for Ti2p3/2 line between TiN and TixAl1-xN th77pj in film was 0.7 eV.展开更多
This paper reports that the transient laser-induced voltages have been observed in La2/3Ca1/3MnO3 thin films on MgO (001) in the absence of an applied current. A peak voltage of - 0.15 V was detected in response to ...This paper reports that the transient laser-induced voltages have been observed in La2/3Ca1/3MnO3 thin films on MgO (001) in the absence of an applied current. A peak voltage of - 0.15 V was detected in response to 0.015J pulse of 308 nm laser. It is demonstrated that the signal polarity is reversed when the films are irradiated through the substrate rather than at the air/film interface. Off-diagonal thermoelectricity may support the inversion of the signal when the irradiation direction is reversed.展开更多
The perovskite bilayers La0.67Ca0.33MnO3 (LCMO) (100 nm) / La0.67Sr0.33MnO3(LSMO) (100 nm) and LSMO (100 nm) / LCMO (100 nm) are fabricated by a facing-target sputtering technique. Their transport and magn...The perovskite bilayers La0.67Ca0.33MnO3 (LCMO) (100 nm) / La0.67Sr0.33MnO3(LSMO) (100 nm) and LSMO (100 nm) / LCMO (100 nm) are fabricated by a facing-target sputtering technique. Their transport and magnetic properties are investigated. It is found that the transport properties between them are different obviously due to distinguishable structures, and the different lattice strains in both films result in the difference of metal-to-insulator transition. Only single-step magnetization loop appears in our bilayers from 5K to 320K, and the coercive force of LSMO/LCMO varies irregularly with a minimum ~ 2387A/m which is lower than that of LCMO and LSMO single layer films. The behaviour is explained by some magnetic coupling.展开更多
By using local theory and taking into account retardation,we investigate the plasmonpolariton modes of a finite Cantor-type heterostructures which are composed of two alternating materials with their thicknesses follo...By using local theory and taking into account retardation,we investigate the plasmonpolariton modes of a finite Cantor-type heterostructures which are composed of two alternating materials with their thicknesses following Cantor sequence.The effects of an external magnetic field applied parallel to the interfaces are considered.We find that the modes have fractal structure due to the special geometry of the system,and the dispersion relations of the modes are strikingly modified by the external magnetic field.Some new modes appear because of the application of the field.By plotting the profiles of the amplitudes of the electric field,we also investigate the localization properties of the modes.展开更多
Room-temperature 1.54-μm photoluminescence(PL)is observed from Er-doped Si-rich SiO_(2)(SiO_(2):Si:Er)films deposited by using the magnetron sputtering technique.To determine the optimum Si content in the SiO_(2):Si:...Room-temperature 1.54-μm photoluminescence(PL)is observed from Er-doped Si-rich SiO_(2)(SiO_(2):Si:Er)films deposited by using the magnetron sputtering technique.To determine the optimum Si content in the SiO_(2):Si:Er films,the percentage area of the Si target in the composite SiO_(2)-Si-Er target was changed from 0,to 10%,20%and 30%.The percentage area of the Er target was fixed at 1%.It is found that the optimum annealing temperatures for Er3+luminescence intensities are 900°C for the SiO_(2):Er film and 900,800,and 700°C for the SiO_(2):Si:Er films containing 10%,20%and 30%excess-Si(percentage areas of Si target),respectively.The SiO_(2):Si:Er film containing 20%excess-Si and annealed at 800°C has the intensest PL.展开更多
Investigations of alloying Re and Ru in the [110](001) dislocation core of the Ni/Ni3Al interface were conducted within the framework of density functional theory. The energetic calculations show that both elements ...Investigations of alloying Re and Ru in the [110](001) dislocation core of the Ni/Ni3Al interface were conducted within the framework of density functional theory. The energetic calculations show that both elements can stabilize the [110](001) dislocation core. In the dislocation core region, Re and Ru prefer to substitute for Ni on the site in the γ-phase. Re is easier to segregate into the dislocation core region as compared with Ru; it especially prefers to substitute for Ni on the γ-(Ni)1 site.展开更多
We theoretically investigate the spin current for a parabolically confined semiconductor heterojunction quantum wire with weak Rashba spin-orbit coupling by means of the perturbation method. By analytical calculation,...We theoretically investigate the spin current for a parabolically confined semiconductor heterojunction quantum wire with weak Rashba spin-orbit coupling by means of the perturbation method. By analytical calculation, it is found that only two components of spin current density is non-zero in the equilibrium case. Numerical examples have demonstrated that the spin current of electron transverse motion is 10^-3 times that of electron longitudinal motion. However, the former one is much more sensitive to the strength of Rashba spin-orbit coupling. These results may suggest an approach to the spin storage device and to the measurement of spin current through its induced electric field.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 50971056 and 51171057)the Youth Natural Science Foundation of Hebei Province (No. E2011202002)
文摘The variations of magnetization and magneto- striction with temperature and stress were investigated through the analysis of the effective field, induced by temperature and stress. A nonlinear magnetostrictive model of giant magnetostrictive materials was proposed. The proposed model can be used to calculate the magnetostrictive characterization of giant magnetostrictive materi- als in different temperatures and under different stresses. The coupling effects of axial stress, magnetic field, and temperature on the magnetostriction of a Terfenol-D rod were numerically simulated as well as experimentally tested. Comparison between the calculating and experimental results shows that the proposed model can better describe the magneto-thermo-mechanical characteristics of Terfenol-D rod under different temperatures and compressive stress. Therefore, the proposed model possesses an important significance for the design of magnetostrictive devices.
基金Supported by the Program for New Century Excellent Talents in University(No NCET-08-0841)the Beijing Natural Science Foundation(No 4122064)the Foresight Fund Program from China University of Petroleum(Beijing)(No QZDX-2010-01).
文摘The quantitative analysis of zinc isopropyl-isooctyl-dithiophosphate (T204) mixed with lube base oil from Korea with viscosity index 70 (T204-Korea70) is presented by using terahertz time-domain spectroscopy (THz-TDS).Compared with the middle-infrared spectra of zinc n-butyl-isooctyl-dithiophosphate (T202) and T204,THz spectra of T202 and T204 show the weak broad absorption bands.Then,the absorption coefficients of the T204-Korea70 system follow Beer's law at the concentration from 0.124 to 4.024%.The experimental absorption spectra of T204-Korea70 agree with the calculated ones based on the standard absorption coefficients of T204 and Korea70.The quantitative analysis enables a strategy to monitor the formulation of lubricating oil in real time.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB606402)the National Natural Science Foundation of China(Grant No.51071091)
文摘An Ni-AI-Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3A1) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, A1) random solid solutions are calculated as a function of the concentrations of Co and A1. The calculated SFEs decrease with increasing concentrations of Co and A1, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni(Co) solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ(Ni) may be improved by the addition of Co.
基金Supported by the National Natural Science Foundation of China under Grant No 10574042, the Specialized Research Fund for the Doctoral Prozram of Hizher Education of China under Grant No 20060542002, and the Hunan Provincial Natural Science Foundation of China under Grant No 06JJ2097
文摘We study theoretically the electronic and transport property for an armchair-edge graphene nanoribbon (GNR.) with 12 and 11 transversal atomic lines, respectively. The ONR. is irradiated under an external longitudinal polarized high-frequency electromagnetic field at low temperatures. Within the framework of linear response theory in the perturbative regime, we examine the joint density of states and the real conductance of the system. It is demonstrated that, by numerical examples, some new photon-assisted intersubband transitions over a certain range of field frequency exist with different selection rules from those of both zigzag-edge GNR. and single-walled carbon nanotube. This opto-electron property dependence of armchair-edge GNR. on field frequency may be used to detect the high-frequency electromagnetic irradiation.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574042) and the Guizhou Provincial Science and Technology Foundation of China (Grant No 20052088).
文摘This paper investigates theoretically the electronic structure and transport of a two-level quantum dot irradiated under a strong laser field at low temperatures. Using the method of Keldysh equation of motion for nonequilibrium Green functions, it examines the time-averaged density of states and conductance for the system with photon polarization parallel with and perpendicular to the tunnelling current direction respectively. It is demonstrated that, by analysing some numerical examples, more photon sidebands resonance states and multi-and single-photon transitions are found when diagonal matrix elements dominate the interaction, while the electronic transitions due to multiphoton absorption are more or less suppressed when off-diagonal interaction dominates.
基金Supported by the National Natural Science Foundation of China under Grant No 10574042, and the Guizhou Provincial Science and Technology Foundation of China under Grant No 20052088.
文摘We investigate theoretically the electron transport of a two-level quantum dot irradiated under a weak laser field at low temperatures in the rotating wave approximation. Using the method of the Keldysh equation of motion for nonequilibrium Green function, we examine the conductance for the system with photon polarization perpendicular to the tunnelling current direction. It is demonstrated that by analytic analysing and numerical examples, a feature of conductance peak splitting appears, and the dependence of conductance on the incident laser frequency and self-energy are discussed.
基金Supported by the National Natural Science Foundation of China。
文摘A new class of 1D quasiperiodic lattices,for which the substitution rules are B→BA,and A→BAB,has been studied in several aspects.The high-dimensional projection method for obtaining the quasilattice is presented.A multifractral spectral behavior and gap fabeling properties have been found,which display the perfect quasiperiodicity of the studied model.
基金Supported by the National Natural Science Foundation of China,and in part by the International Program in the Physical Sciences,Uppsala University,Sweden.
文摘By using the Hardy-Wright-Mobius inverse formula,we have improved the Carlsson-Gelatt-Ehrenreich scheme for the inverse problem of cohesive energy.The advantage of the new method is that the inverse formula are in a sense independent of the geometries of lattices.
基金Supported by the National Natural Science Foundation of China under Grant No 10574042, and the Research Foundation of Hunan Education Commission under Grant No 04A031.
文摘We theoretically study the low temperature electron transport properties of a weak Rashba spin-orbit coupling (SOC) semiconductor quantum wire connected nonadiabatically to two electrode leads without SOC. The wire and the leads are defined by a parabolic confining potential, and the influence of both the wire-lead connection and the Rashba SOC on the electron transport is treated analytically by means of scattering matrix within effective free-electron approximation. From analytical analysis and numerical examples, we find that the system shows some fractional quantum conductance behaviour, and for some particular wire width a pure spin polarized current exists. Our result may imply a simple method for the design of a spin filter without involving any magnetic materials or magnetic fields.
基金supported by the National Natural Science Foundation of China (Nos.50571034 and 50971056) and the State Key Laboratory of Powder Metallurgy,Central South University
基金Supported by the National Natural Science Foundation of China(Nos30370406, 10374022 and 10674034)
文摘ZrSiO4 and coesite were obtained under high-pressure and high-temperature from the nano precursor of a-SiO2 and ZrO2. XRD and Raman measurements indicate that ZrSiO4 was formed at a temperature higher than 920 ℃ under a pressure of 3.6 GPa. As the pressure increased to 3.9 GPa, the ZrSiO4 formation temperature was reduced to 815 ℃. The formation temperature for coesite was 990 ℃ under 3.9 GPa. The lower formation temperature for ZrSiO4, as compared to that for coesite, provided an experimental evidence that the coesite in the Earth's surface usually occurs as inclusions in ZrSiO4.
基金National Natural Science Foundation of China under Grant No.10374068the Doctoral Education Fund of the Ministry of Education of China under Grant No.20050610011
文摘We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependentrotating magnetic field.Based on the algebraic structure of the non-autonomous system,the exact solution of theSchrdinger equation is obtained by using the method of algebraic dynamics.Based on the time-dependent analyticalsolution,we further study the entanglement evolution between the two coupled spins for different initial states,and findthat the entanglement is determined by the coefficients of the initial state and the coupling constant J of the system.
基金Supported by the National Natural Science Foundation of China under Grant No 30370406.
文摘We examine RCoO3 (R=La, Ce, Pr, Nd, Sin, Eu, Gd, and Dy) perovskites prepared with the solid-state reaction method by Raman spectroscopy, and report the Raman active phonons in the RCoO3 perovskites crystallized in cubic symmetry for RCoO3 (R=La, Ce, Pr and Nd) and orthorhombic symmetry for RCoO3 (R=Sm, Eu, Gd, and Dy). It is found that the Raman spectra of RCoO3 perovskites are strongly dependent on the ionic radius of the rare earth elements, and the frequency shift of the most intense modes of the orthorhombic samples are correlated with some structural parameters such as Co-O bond distances, ionic radius of the rare earth elements and Jahn-Teller distortion. It is clear that Raman spectroscopy has the advantage of sensitivity to structure distortion and oxygen motion.
基金This work was supported by the National Natural Science Foundation of China under grant No.10474074the Hubei Natural Science Foundation under grant No.2001ABB060.
文摘TixAl1-xN films have been prepared by RF reactive magnetron sputtering. X-ray diffraction results showed that TixAl1-xN thin films in this study were hexagonal wurtzite structure with the Ti content up to 0.18. X-ray photoelectron spectrocopy studies provided that the Nls core-electron spectrum of TixAl1-xN thin film brodend with increasing Ti content, and the difference of the chemical shifts for Ti2p3/2 line between TiN and TixAl1-xN th77pj in film was 0.7 eV.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60576015 and 50672132).
文摘This paper reports that the transient laser-induced voltages have been observed in La2/3Ca1/3MnO3 thin films on MgO (001) in the absence of an applied current. A peak voltage of - 0.15 V was detected in response to 0.015J pulse of 308 nm laser. It is demonstrated that the signal polarity is reversed when the films are irradiated through the substrate rather than at the air/film interface. Off-diagonal thermoelectricity may support the inversion of the signal when the irradiation direction is reversed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50371102 and 10334070), Hi-Tech Research and Development Program of China (Grant No 2004AA32G090), the Research Foundation of Shandong Provincial Education Department of China (Grant No 03A05), the Hong Kong Research Grant Council, and China Postdoctoral Science Foundation.
文摘The perovskite bilayers La0.67Ca0.33MnO3 (LCMO) (100 nm) / La0.67Sr0.33MnO3(LSMO) (100 nm) and LSMO (100 nm) / LCMO (100 nm) are fabricated by a facing-target sputtering technique. Their transport and magnetic properties are investigated. It is found that the transport properties between them are different obviously due to distinguishable structures, and the different lattice strains in both films result in the difference of metal-to-insulator transition. Only single-step magnetization loop appears in our bilayers from 5K to 320K, and the coercive force of LSMO/LCMO varies irregularly with a minimum ~ 2387A/m which is lower than that of LCMO and LSMO single layer films. The behaviour is explained by some magnetic coupling.
基金the Chinese National Advanced Technology Foundation through grant No.040-144-05-085.
文摘By using local theory and taking into account retardation,we investigate the plasmonpolariton modes of a finite Cantor-type heterostructures which are composed of two alternating materials with their thicknesses following Cantor sequence.The effects of an external magnetic field applied parallel to the interfaces are considered.We find that the modes have fractal structure due to the special geometry of the system,and the dispersion relations of the modes are strikingly modified by the external magnetic field.Some new modes appear because of the application of the field.By plotting the profiles of the amplitudes of the electric field,we also investigate the localization properties of the modes.
基金Supported by the National Natural Science Foundation of China under Grant No.59832100the State Key Laboratory on Integrated Optoelectronics。
文摘Room-temperature 1.54-μm photoluminescence(PL)is observed from Er-doped Si-rich SiO_(2)(SiO_(2):Si:Er)films deposited by using the magnetron sputtering technique.To determine the optimum Si content in the SiO_(2):Si:Er films,the percentage area of the Si target in the composite SiO_(2)-Si-Er target was changed from 0,to 10%,20%and 30%.The percentage area of the Er target was fixed at 1%.It is found that the optimum annealing temperatures for Er3+luminescence intensities are 900°C for the SiO_(2):Er film and 900,800,and 700°C for the SiO_(2):Si:Er films containing 10%,20%and 30%excess-Si(percentage areas of Si target),respectively.The SiO_(2):Si:Er film containing 20%excess-Si and annealed at 800°C has the intensest PL.
基金supported by the National Key Basic Research Program of China (Grant No 2006CB605102)
文摘Investigations of alloying Re and Ru in the [110](001) dislocation core of the Ni/Ni3Al interface were conducted within the framework of density functional theory. The energetic calculations show that both elements can stabilize the [110](001) dislocation core. In the dislocation core region, Re and Ru prefer to substitute for Ni on the site in the γ-phase. Re is easier to segregate into the dislocation core region as compared with Ru; it especially prefers to substitute for Ni on the γ-(Ni)1 site.
基金Supported by the National Natural Science Foundation of China under Grant No 10574042, and the Natural Science Foundation of Hunan Province under Grant No 06JJ2097.
文摘We theoretically investigate the spin current for a parabolically confined semiconductor heterojunction quantum wire with weak Rashba spin-orbit coupling by means of the perturbation method. By analytical calculation, it is found that only two components of spin current density is non-zero in the equilibrium case. Numerical examples have demonstrated that the spin current of electron transverse motion is 10^-3 times that of electron longitudinal motion. However, the former one is much more sensitive to the strength of Rashba spin-orbit coupling. These results may suggest an approach to the spin storage device and to the measurement of spin current through its induced electric field.