The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical per...The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical performance of layered films. The influence of periods on microstructure, adhesion and hardness of [Ti/TiB2]n multilayered films was studied. X-ray diffraction （XRD） analysis shows that the monolayer TiB2 films exhibit （001） preferred orientation, and the preferred orientation of [Ti/TiB2], multilayered films transfers from （001） to （100） with the increase of periods. The cross-sectional morphology of each film displays homogeneity by field emission scanning electron microscopy （FESEM）. The hardness of the films measured via nanoindention changes from 20 to 26 GPa with the increase of periods. These values of hardness are a bit lower than that of the monolayer TiB2 films which is up to 33 GPa. However, the [Ti/TiB2]n multilayered films present a considerably good adhesion, which reaches a maximum of 24 N, in comparison with the monolayer TiB2 films according to the experimental results.展开更多
In order to investigate nanomechanical properties of nanostructured Ti metallic material, pure Ti films were prepared by magnetron sputtering at the bias voltage of 0-140 V. The microstructure of Ti films was characte...In order to investigate nanomechanical properties of nanostructured Ti metallic material, pure Ti films were prepared by magnetron sputtering at the bias voltage of 0-140 V. The microstructure of Ti films was characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and high-resolution transmission electron microscopy（HRTEM）. It is interesting to find that the microstructure of pure Ti films was characterized by the composite structure of amorphous-like matrix embodied with nanocrystallines, and the crystallization was improved with the increase of bias voltage. The hardness of Ti films measured by nanoindentation tests shows a linear relationship with grain sizes in the scale of 6-15 nm. However, the pure Ti films exhibit a soft tendency characterized by a smaller slope of Hall-Petch relationship. In addition, the effect of bias voltage on the growth orientation of Ti films was discussed.展开更多
Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and super...Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and superparamagnetic properties.When the substrate temperature increases from room temperature to 400℃,Co particles gradually grow,and the degree of Co oxidation significantly decreases.Consequently,the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400℃.At a high substrate temperature,conductive pathways form among some of the clustered Co particles.Thus,resistivity rapidly declines from 1600 to 76μΩ·m.The magnetoresistive characteristic of Co−TiO2 films is achieved even at resistivity of as low as 76μΩ·m.These results reveal that the obtained nanocomposite films have low Co oxidation,high magnetization and magnetoresistance at room temperature.展开更多
Si-rich silicon oxide films were deposited by RF magnetron sputtering onto composite Si/SiO2 targets. After annealed at different temperature, the silicon oxide films embedded with silicon nanocrystals were obtained. ...Si-rich silicon oxide films were deposited by RF magnetron sputtering onto composite Si/SiO2 targets. After annealed at different temperature, the silicon oxide films embedded with silicon nanocrystals were obtained. The photoluminescenee（PL） from the silicon oxide films embedded with silicon nanocrystals was observed at room temperature. The strong peak is at 360 nm, its position is independent of the annealing temperature. The origin of the 360-nm PL in the silicon oxide films embedded with silicon nanoerystals was discussed.展开更多
The nanocrystalline SiC films were prepared on Si then annealed at 800℃ and 1 000℃ for 30 minutes （111） substrates by rf magnetron sputtering and in a vacuum annealing system. The crystal structure and crystalliza...The nanocrystalline SiC films were prepared on Si then annealed at 800℃ and 1 000℃ for 30 minutes （111） substrates by rf magnetron sputtering and in a vacuum annealing system. The crystal structure and crystallization of as-annealed SiC films were determined by the Fourier transform infrared （FIR） absorption spectra and the X-ray diffraction （XRD） analysis. Measurement of photoluminescence （PL） of the nanocrystalline SiC （nc-SiC） films shows that the blue light with 473 nm and 477 nm wavelengths emitted at room temperature and that the PL peak shifts to shorter wavelength side and the PL intensity becomes stronger as the annealing temperature decreases. The time-resolved spectrum of the PL at 477 nm exhibits a bi-exponential decay process with lifetimes of 600 ps and 5 ns and a characteristic of the direct band gap. The strong blue light emission with short PL lifetimes suggests that the quantum confinement effect of the SiC nanocrystals resulted in the radiative recombination of the direct optical transitions.展开更多
The Nd Fe B/Co multilayer films were prepared by magnetron sputtering. After that, the samples were annealed at 600 ℃ for 20 min. The surface morphology, phase structures and magnetic properties of Mo（50 nm）/[Nd F...The Nd Fe B/Co multilayer films were prepared by magnetron sputtering. After that, the samples were annealed at 600 ℃ for 20 min. The surface morphology, phase structures and magnetic properties of Mo（50 nm）/[Nd Fe B（100 nm）/Co（y）]×10/Mo（50 nm） thin films were researched by AFM, XRD and VSM, respectively. The results show that the films show stronger perpendicular magnetic anisotropy. When the thickness of Co layers is 10 nm, the coercivity Hc⊥ is the maximum, 295 k A/m. However, for y=10-20, the reduced remanence M/Ms of films has increased. When the thickness of Co layers is 20-30 nm, the Nd Fe B/Co multilayer films obtained more superior magnetic properties with M/Ms =0.95.展开更多
The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pu...The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pulses and also the samples of data recording devices on the spin storage medium are described. The study used a film with perpendicular anisotropy （Tb22Co5Fe73/Pr6O11/Tb29Co5Fe76, Tb25Co5Fe70/Al2O3, Tb22Co5Fe73, Tb19Co5Fe76） and films planar single-axis magnetic anisotropy （Co80Fe20/Pr6O11/CO30Fe70）. The magnetic switching of magnetic layers under action the magnetic field of a spin current is the most important for practical use in elements of spintronic. The spin current can also be realized using short electrical pulses. On the basis of this mechanism, the high-speed recording of information on the spin carrier has been realized.展开更多
基金Project(51175212)supported by the National Natural Science Foundation of China
文摘The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical performance of layered films. The influence of periods on microstructure, adhesion and hardness of [Ti/TiB2]n multilayered films was studied. X-ray diffraction （XRD） analysis shows that the monolayer TiB2 films exhibit （001） preferred orientation, and the preferred orientation of [Ti/TiB2], multilayered films transfers from （001） to （100） with the increase of periods. The cross-sectional morphology of each film displays homogeneity by field emission scanning electron microscopy （FESEM）. The hardness of the films measured via nanoindention changes from 20 to 26 GPa with the increase of periods. These values of hardness are a bit lower than that of the monolayer TiB2 films which is up to 33 GPa. However, the [Ti/TiB2]n multilayered films present a considerably good adhesion, which reaches a maximum of 24 N, in comparison with the monolayer TiB2 films according to the experimental results.
基金Projects(51102264,51271123)supported by the National Natural Science Foundation of ChinaProjects(5313310202,13ZR1427900)supported by Shanghai Municipal Education Commission,China
文摘In order to investigate nanomechanical properties of nanostructured Ti metallic material, pure Ti films were prepared by magnetron sputtering at the bias voltage of 0-140 V. The microstructure of Ti films was characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and high-resolution transmission electron microscopy（HRTEM）. It is interesting to find that the microstructure of pure Ti films was characterized by the composite structure of amorphous-like matrix embodied with nanocrystallines, and the crystallization was improved with the increase of bias voltage. The hardness of Ti films measured by nanoindentation tests shows a linear relationship with grain sizes in the scale of 6-15 nm. However, the pure Ti films exhibit a soft tendency characterized by a smaller slope of Hall-Petch relationship. In addition, the effect of bias voltage on the growth orientation of Ti films was discussed.
基金Project(2016YFE0205700)supported by the National Key Research and Development Program of ChinaProject(18JCYBJC18000)supported by the Natural Science Foundation of Tianjin City,China。
文摘Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and superparamagnetic properties.When the substrate temperature increases from room temperature to 400℃,Co particles gradually grow,and the degree of Co oxidation significantly decreases.Consequently,the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400℃.At a high substrate temperature,conductive pathways form among some of the clustered Co particles.Thus,resistivity rapidly declines from 1600 to 76μΩ·m.The magnetoresistive characteristic of Co−TiO2 films is achieved even at resistivity of as low as 76μΩ·m.These results reveal that the obtained nanocomposite films have low Co oxidation,high magnetization and magnetoresistance at room temperature.
基金National Natural Science Foundation of China(60336010)
文摘Si-rich silicon oxide films were deposited by RF magnetron sputtering onto composite Si/SiO2 targets. After annealed at different temperature, the silicon oxide films embedded with silicon nanocrystals were obtained. The photoluminescenee（PL） from the silicon oxide films embedded with silicon nanocrystals was observed at room temperature. The strong peak is at 360 nm, its position is independent of the annealing temperature. The origin of the 360-nm PL in the silicon oxide films embedded with silicon nanoerystals was discussed.
基金The project supported by the National Natural Science Founda-tion of China(Grant No.60476003)
文摘The nanocrystalline SiC films were prepared on Si then annealed at 800℃ and 1 000℃ for 30 minutes （111） substrates by rf magnetron sputtering and in a vacuum annealing system. The crystal structure and crystallization of as-annealed SiC films were determined by the Fourier transform infrared （FIR） absorption spectra and the X-ray diffraction （XRD） analysis. Measurement of photoluminescence （PL） of the nanocrystalline SiC （nc-SiC） films shows that the blue light with 473 nm and 477 nm wavelengths emitted at room temperature and that the PL peak shifts to shorter wavelength side and the PL intensity becomes stronger as the annealing temperature decreases. The time-resolved spectrum of the PL at 477 nm exhibits a bi-exponential decay process with lifetimes of 600 ps and 5 ns and a characteristic of the direct band gap. The strong blue light emission with short PL lifetimes suggests that the quantum confinement effect of the SiC nanocrystals resulted in the radiative recombination of the direct optical transitions.
文摘The Nd Fe B/Co multilayer films were prepared by magnetron sputtering. After that, the samples were annealed at 600 ℃ for 20 min. The surface morphology, phase structures and magnetic properties of Mo（50 nm）/[Nd Fe B（100 nm）/Co（y）]×10/Mo（50 nm） thin films were researched by AFM, XRD and VSM, respectively. The results show that the films show stronger perpendicular magnetic anisotropy. When the thickness of Co layers is 10 nm, the coercivity Hc⊥ is the maximum, 295 k A/m. However, for y=10-20, the reduced remanence M/Ms of films has increased. When the thickness of Co layers is 20-30 nm, the Nd Fe B/Co multilayer films obtained more superior magnetic properties with M/Ms =0.95.
文摘The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pulses and also the samples of data recording devices on the spin storage medium are described. The study used a film with perpendicular anisotropy （Tb22Co5Fe73/Pr6O11/Tb29Co5Fe76, Tb25Co5Fe70/Al2O3, Tb22Co5Fe73, Tb19Co5Fe76） and films planar single-axis magnetic anisotropy （Co80Fe20/Pr6O11/CO30Fe70）. The magnetic switching of magnetic layers under action the magnetic field of a spin current is the most important for practical use in elements of spintronic. The spin current can also be realized using short electrical pulses. On the basis of this mechanism, the high-speed recording of information on the spin carrier has been realized.
