Pulsed laser deposition(PLD) is emerging as the most rapid and efficient technique for fabricating the many compound films. ZnO thin films can be prepared under various deposition conditions by PLD. The effects of var...Pulsed laser deposition(PLD) is emerging as the most rapid and efficient technique for fabricating the many compound films. ZnO thin films can be prepared under various deposition conditions by PLD. The effects of various substrate temperature, oxygen partial pressure, annealing temperature, substrate, buffer layers thickness and film thickness on micro-structural, optical and electrical properties of ZnO films grown by PLD technology are reviewed. ZnO films with special function can grow under proper conditions by PLD.展开更多
A nonlinear optical loop mirror constructed from step-decreasing-dispersion fiber instead of DDF is used to compress optical pulse.Numerical simulations show that the effect of the proposed method is close to that of ...A nonlinear optical loop mirror constructed from step-decreasing-dispersion fiber instead of DDF is used to compress optical pulse.Numerical simulations show that the effect of the proposed method is close to that of the method based on DDF.It not only resolves the difficulty of the making of DDF but also makes the design of the system more convenient.展开更多
Proposed is a novel optical pulse compression technique based on high-doped erbium fiber amplifier and standard single-mode fiber(SMF). We used the amplifier with the erbium ion concentration of 6.3×10-3 to ampli...Proposed is a novel optical pulse compression technique based on high-doped erbium fiber amplifier and standard single-mode fiber(SMF). We used the amplifier with the erbium ion concentration of 6.3×10-3 to amplify a hyperbolic secant pulse from a regeneratively mode-locked fiber laser. The central wavelength, pulsewidth and peak power of the pulse are 1 550 nm, 12.5 ps and 3 mW, respectively. Then the amplified pulse with peak power level corresponding to a higher-order soliton is compressed when it propagates through a 3-km-long single-mode fiber. Studied are the compressed pulses under different pump powers and fiber lengths. The results show that it can get a narrower pulse, and solve the difficulty that pulses at low power can not be compressed directly in the fiber. And the construct is compact.展开更多
The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon ener...The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon energy 〉 5 keV and duration 10-20 ns has been detected. It has been shown that the x-ray pulse is due to the ＂runaway＂ of electrons from the head of an anode-directed streamer. The estimated maximum bremsstrahlung energy is about 5-10 keV. The presence of a maximum in the bremsstrahlung spectrum is due to that the photons emitted by electrons are absorbed by atoms of the gas in which the discharge operates.展开更多
In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in...In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in It. G. Durfee Ⅲ, S. Backus, M.M. Murnane, and H.C. Kapteyn, Opt. Left. 22 （1997） 1565]. Some possible factors, which produce the contradiction, are discussed briefly.展开更多
Rare-earth orthoferrite SmFeO3 is an outstanding single-phase multiferroic material,holding great potential in novel low-power electronic devices.Nevertheless,simultaneous magnetic and ferroelectric orders as well as ...Rare-earth orthoferrite SmFeO3 is an outstanding single-phase multiferroic material,holding great potential in novel low-power electronic devices.Nevertheless,simultaneous magnetic and ferroelectric orders as well as magnetoelectric(ME)coupling effect at room temperature(RT)in this system have not been demonstrated yet.In this study,epitaxial SmFeO3 films were successfully prepared onto tensile-strain Nb-SrTiO3(Nb-STO)substrates by a pulsed laser deposition(PLD)method.Measurement results show that the films exhibit obvious ferromagnetic and ferroelectric orders at RT.Meanwhile,the magnetic anisotropy gradually changes from out-of-plane(OP)to in-plane(IP)direction with increasing film thickness,which is attributed to the variations of O 2p-Fe 3d hybridization intensity and Fe 3d-orbit occupancy caused by the strain-relaxed effect.Moreover,electrically driven reversible magnetic switching further proves that the SmFeO3 films exhibit the RT ME coupling effect,suggesting promising applications in new-generation electric-write magnetic-read data storage devices.展开更多
In this work, epitaxial growth of LaMnO3 thin films on different substrates using pulsed laser deposition under tensile and compressive strain was studied. The intrinsic exchange bias effect was observed in the single...In this work, epitaxial growth of LaMnO3 thin films on different substrates using pulsed laser deposition under tensile and compressive strain was studied. The intrinsic exchange bias effect was observed in the single A-type antiferromagnetic LaMnO3 films no matter whether the tensile or compressive strain was supplied by the substrates. Due to the lattice mismatch between the film and different substrates, the intense strain can induce MnO6 octahedral rotation in the bottom region of the film neighboring the substrate, which leads to the distortion of MnO6 octahedron and the net magnetic behavior. However, the upper part maintains the original A-type antiferromagnetic order due to strain relaxation. The exchange bias effect in single films is attributed to the coupling between the bottom canted magnetic part and the upper antiferromagnetic region. The observation of exchange bias in single films on different substrates enables the emergence of a new class of biasing components in spintronics, which are based on strain-engineering.展开更多
Three types of a-C:Co/Si samples were fabricated using the pulsed laser deposition: Co2-C98/8i with Co dispersed in the a-C film, Co2-C98/Si with Co segregated at the interface, and a-C/Co/Si with Co continuously dist...Three types of a-C:Co/Si samples were fabricated using the pulsed laser deposition: Co2-C98/8i with Co dispersed in the a-C film, Co2-C98/Si with Co segregated at the interface, and a-C/Co/Si with Co continuously distributed at the a-C/Si interface. Both types of Co2-C98/Si samples had the positive bias-voltage-dependent magnetoresistance (MR) at 300 K, and all MRs had saturated behavior. The study on the electrotransport properties indicated that the MR appeared in the diffusion current region, and the mechanism of MR was proposed to be that the applied magnetic field and local random magnetic field caused by the superparamagnetic Co particles modulate the ratio of singlet and triplet spin states, resulting in the MR effect. In addition, the very different physical and structural properties of all samples revealed that Co played a crucial role in the room-temperature positive MR of a-C:Co/Si system.展开更多
文摘Pulsed laser deposition(PLD) is emerging as the most rapid and efficient technique for fabricating the many compound films. ZnO thin films can be prepared under various deposition conditions by PLD. The effects of various substrate temperature, oxygen partial pressure, annealing temperature, substrate, buffer layers thickness and film thickness on micro-structural, optical and electrical properties of ZnO films grown by PLD technology are reviewed. ZnO films with special function can grow under proper conditions by PLD.
文摘A nonlinear optical loop mirror constructed from step-decreasing-dispersion fiber instead of DDF is used to compress optical pulse.Numerical simulations show that the effect of the proposed method is close to that of the method based on DDF.It not only resolves the difficulty of the making of DDF but also makes the design of the system more convenient.
基金National Natural Science Foundation of China(60507001 60477022 06YFGPGX08500)
文摘Proposed is a novel optical pulse compression technique based on high-doped erbium fiber amplifier and standard single-mode fiber(SMF). We used the amplifier with the erbium ion concentration of 6.3×10-3 to amplify a hyperbolic secant pulse from a regeneratively mode-locked fiber laser. The central wavelength, pulsewidth and peak power of the pulse are 1 550 nm, 12.5 ps and 3 mW, respectively. Then the amplified pulse with peak power level corresponding to a higher-order soliton is compressed when it propagates through a 3-km-long single-mode fiber. Studied are the compressed pulses under different pump powers and fiber lengths. The results show that it can get a narrower pulse, and solve the difficulty that pulses at low power can not be compressed directly in the fiber. And the construct is compact.
文摘The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon energy 〉 5 keV and duration 10-20 ns has been detected. It has been shown that the x-ray pulse is due to the ＂runaway＂ of electrons from the head of an anode-directed streamer. The estimated maximum bremsstrahlung energy is about 5-10 keV. The presence of a maximum in the bremsstrahlung spectrum is due to that the photons emitted by electrons are absorbed by atoms of the gas in which the discharge operates.
基金The project supported by National Natural Science Foundation of China under Grant No. 90103025 and the Research Fund for the Doctoral Program of Higher .Education of China under Grant No. 20020027006
文摘In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in It. G. Durfee Ⅲ, S. Backus, M.M. Murnane, and H.C. Kapteyn, Opt. Left. 22 （1997） 1565]. Some possible factors, which produce the contradiction, are discussed briefly.
基金This work was supported by the National Natural Science Foundation of China(51871137,51901118,51571136 and 61904099).The authors acknowledge Shanghai Synchrotron Radiation Facility at the Beamline BL08U1A and the National Synchrotron Radiation Laboratory at the Beamline BL12-a for the XAS measurements.
文摘Rare-earth orthoferrite SmFeO3 is an outstanding single-phase multiferroic material,holding great potential in novel low-power electronic devices.Nevertheless,simultaneous magnetic and ferroelectric orders as well as magnetoelectric(ME)coupling effect at room temperature(RT)in this system have not been demonstrated yet.In this study,epitaxial SmFeO3 films were successfully prepared onto tensile-strain Nb-SrTiO3(Nb-STO)substrates by a pulsed laser deposition(PLD)method.Measurement results show that the films exhibit obvious ferromagnetic and ferroelectric orders at RT.Meanwhile,the magnetic anisotropy gradually changes from out-of-plane(OP)to in-plane(IP)direction with increasing film thickness,which is attributed to the variations of O 2p-Fe 3d hybridization intensity and Fe 3d-orbit occupancy caused by the strain-relaxed effect.Moreover,electrically driven reversible magnetic switching further proves that the SmFeO3 films exhibit the RT ME coupling effect,suggesting promising applications in new-generation electric-write magnetic-read data storage devices.
基金financially supported by the National Key R&D Program of China (2017YFB0405703)the National Natural Science Foundation of China (51871137, 61434002 and 51571136)the Special Funds of Sanjin Scholars Program
文摘In this work, epitaxial growth of LaMnO3 thin films on different substrates using pulsed laser deposition under tensile and compressive strain was studied. The intrinsic exchange bias effect was observed in the single A-type antiferromagnetic LaMnO3 films no matter whether the tensile or compressive strain was supplied by the substrates. Due to the lattice mismatch between the film and different substrates, the intense strain can induce MnO6 octahedral rotation in the bottom region of the film neighboring the substrate, which leads to the distortion of MnO6 octahedron and the net magnetic behavior. However, the upper part maintains the original A-type antiferromagnetic order due to strain relaxation. The exchange bias effect in single films is attributed to the coupling between the bottom canted magnetic part and the upper antiferromagnetic region. The observation of exchange bias in single films on different substrates enables the emergence of a new class of biasing components in spintronics, which are based on strain-engineering.
基金support given by the National Natural Science Foundation of China (Grant Nos. U0734001 and 50772054)the Ministry of Science and Technology of China (Grant Nos. 2008CB617601 and 2009CB929202)
文摘Three types of a-C:Co/Si samples were fabricated using the pulsed laser deposition: Co2-C98/8i with Co dispersed in the a-C film, Co2-C98/Si with Co segregated at the interface, and a-C/Co/Si with Co continuously distributed at the a-C/Si interface. Both types of Co2-C98/Si samples had the positive bias-voltage-dependent magnetoresistance (MR) at 300 K, and all MRs had saturated behavior. The study on the electrotransport properties indicated that the MR appeared in the diffusion current region, and the mechanism of MR was proposed to be that the applied magnetic field and local random magnetic field caused by the superparamagnetic Co particles modulate the ratio of singlet and triplet spin states, resulting in the MR effect. In addition, the very different physical and structural properties of all samples revealed that Co played a crucial role in the room-temperature positive MR of a-C:Co/Si system.
