Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility ...Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility with existing spintronic technology.In this work,we present a tunable room temperature skyrmion platform based on multilayer stacks of MgO/FeNiB/Mo.We systematically studied the creation of magnetic skyrmions in MgO/FeNiB/Mo multilayer structures with perpendicular magnetic anisotropy(PMA).In these structures,the magnetic anisotropy changes from PMA to in-plane magnetic anisotropy(IMA)as the thickness of FeNiB layer increases.By adjusting the applied magnetic field and electric current,stable and high-density skyrmions can be obtained in the material system.The discovery of this material broadens the exploration of new materials for skyrmion and promotes the development of spintronic devices based on skyrmions.展开更多
Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from ...Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from 1.93% to 16.63%,and the center wavelength revealed a blue shift to 0.12 nm with the decrease of background pressure.Grazing incident X-ray diffraction(GIXRD) indicated that multilayers fabricated at high background pressure possessed better periodic structure and thinner Mo-on-Si interlayers.Low crystallization degree in(110) preferred the orientation of Mo layers and serious interdiffusion in the Mo/Si multilayers fabricated at low background pressure were observed by transmission electron microscopy(TEM).According to quantitative analysis of microstructural parameters,the Mo layers thickness and thickness ratio of Mo/Si multilayers both decreased and approached the design value gradually by the decrease of background pressure.In addition,the thicknesses of Mo-on-Si and Si-on-Mo interlayers were 1.17 nm and 0.85 nm respectively.It is suggested that the influence of background pressures on the microstructure has a critical role in determining the optical properties of Mo/Si multilayers.展开更多
In this work,the microstructure and optical properties of the Mo/Si multilayers mirror for the space extreme-ultraviolet solar telescope before and after 100 keV proton irradiation have been investigated.EUV/soft X-ra...In this work,the microstructure and optical properties of the Mo/Si multilayers mirror for the space extreme-ultraviolet solar telescope before and after 100 keV proton irradiation have been investigated.EUV/soft X-ray reflectometer(EXRR) results showed that,after proton irradiation,the reflectivity of the Mo/Si multilayer decreased from 12.20% to 8.34% and the center wavelength revealed red shift of 0.38 nm,as compared with those before proton irradiation.High-resolution transmission electron microscopy(HRTEM) observations revealed the presence of MoSi 2,Mo 3 Si and Mo 5 Si 3 in Mo-on-Si interlayers before irradiation.The preferred orientation such as MoSi 2 with(101) texture and Mo 5 Si 3 with(310) texture was formed in Mo-on-Si interlayers after proton irradiation,which led to the increase of thickness in the interlayers.It is suggested that the changes of microstructures in Mo/Si multilayers under proton irradiation could cause optical properties degradation.展开更多
Mo/Si muitilayer mirrors(30 periods,doublelayer thickness 7nm)with the AZ-PF514 resist pattern whose smallest lines and spaces structure was 0.5pm were etched by reactive ion etching(RIE)in a fluorinated plasma.The et...Mo/Si muitilayer mirrors(30 periods,doublelayer thickness 7nm)with the AZ-PF514 resist pattern whose smallest lines and spaces structure was 0.5pm were etched by reactive ion etching(RIE)in a fluorinated plasma.The etch rate,selectivity and etch profile were investigated as a function of the gas mixture,pressure,and plasma rf power.The groove depth and the etch proHle were investigated by an atomic force microscope before RIE,after RIE and after resist removal.展开更多
The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation.Mo/Si multilayers were annealed at temperature...The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation.Mo/Si multilayers were annealed at temperature ranging from 360 to 770 K,treated with acetone and 5‰NaOH solution,and characterized by small-angle x-ray diffraction technique as well as x-ray photoelectron spectroscopy and Olympus microscopy.展开更多
By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence o...By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence of the multilayer changed to zigzag layered structure at 478 K (=Tzig). Finally, the zigzag structure transformed to Au nanoparticles at 508 K. The distribution of the Au nanoparticles was random within the thin film. In situ X-ray diffraction during heating can clarify partial crystallization Si (c-Si) in the multilayer at 450 K (= ), which corresponds to metal induced crystallization (MIC) from amorphous Si (a-Si) accompanying by Au diffusion. On further heating, a-Au started to crystallize at around 480 K (=Tc) and gradually grew up to 3.2 nm in radius, although the volume of c-Si was almost constant. Continuous heating caused crystal Au (c-Au) melting into liquid AuSi (l-AuSi) at 600 K (= ), which was lower than bulk eutectic temperature ( ). Due to the AuSi eutectic effect, reversible phase transition between liquid and solid occurred once temperature is larger than . Proportionally to the maximum temperatures at each cycles (673, 873 and 1073 K), both and Au crystallization temperature approaches to . Using a thermodynamic theory of the nanoparticle formation in the eutectic system, the relationship between and the nanoparticle size is explained.展开更多
基金Project supported by the National Basic Research Program of China (Grant No.2015CB921403)the National Key Research and Development Program of China (Grant No.2016YFA0300804)+2 种基金the National Natural Science Foundation of China (Grant Nos.51871236,11874408,51431009,92263202,and 51971240)the Science Center of the National Science Foundation of China (Grant No.52088101)the Strategic Priority Research Program (B,Grant No.XDB33030200)of the Chinese Academy of Sciences (CAS)。
文摘Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility with existing spintronic technology.In this work,we present a tunable room temperature skyrmion platform based on multilayer stacks of MgO/FeNiB/Mo.We systematically studied the creation of magnetic skyrmions in MgO/FeNiB/Mo multilayer structures with perpendicular magnetic anisotropy(PMA).In these structures,the magnetic anisotropy changes from PMA to in-plane magnetic anisotropy(IMA)as the thickness of FeNiB layer increases.By adjusting the applied magnetic field and electric current,stable and high-density skyrmions can be obtained in the material system.The discovery of this material broadens the exploration of new materials for skyrmion and promotes the development of spintronic devices based on skyrmions.
基金supported by the National Natural Sciences Foundation of China (Grant No.50671042)the Open Project of State Key Laboratory of Applied Optics (Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences) (Grant No.201004)the Ph.D.Innovation Programs Foundation of Jiangsu Province (Grant No.CXZZ12_0671)
文摘Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from 1.93% to 16.63%,and the center wavelength revealed a blue shift to 0.12 nm with the decrease of background pressure.Grazing incident X-ray diffraction(GIXRD) indicated that multilayers fabricated at high background pressure possessed better periodic structure and thinner Mo-on-Si interlayers.Low crystallization degree in(110) preferred the orientation of Mo layers and serious interdiffusion in the Mo/Si multilayers fabricated at low background pressure were observed by transmission electron microscopy(TEM).According to quantitative analysis of microstructural parameters,the Mo layers thickness and thickness ratio of Mo/Si multilayers both decreased and approached the design value gradually by the decrease of background pressure.In addition,the thicknesses of Mo-on-Si and Si-on-Mo interlayers were 1.17 nm and 0.85 nm respectively.It is suggested that the influence of background pressures on the microstructure has a critical role in determining the optical properties of Mo/Si multilayers.
基金supported by the National Natural Science Foundation of China (Grant No. 50671042)the Open Project of State Key Laboratory of Applied Optics (Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences) (Grant No. 201004)the Ph.D.Innovation Programs Foundation of Jiangsu Province (Grant No.CXZZ12_0671)
文摘In this work,the microstructure and optical properties of the Mo/Si multilayers mirror for the space extreme-ultraviolet solar telescope before and after 100 keV proton irradiation have been investigated.EUV/soft X-ray reflectometer(EXRR) results showed that,after proton irradiation,the reflectivity of the Mo/Si multilayer decreased from 12.20% to 8.34% and the center wavelength revealed red shift of 0.38 nm,as compared with those before proton irradiation.High-resolution transmission electron microscopy(HRTEM) observations revealed the presence of MoSi 2,Mo 3 Si and Mo 5 Si 3 in Mo-on-Si interlayers before irradiation.The preferred orientation such as MoSi 2 with(101) texture and Mo 5 Si 3 with(310) texture was formed in Mo-on-Si interlayers after proton irradiation,which led to the increase of thickness in the interlayers.It is suggested that the changes of microstructures in Mo/Si multilayers under proton irradiation could cause optical properties degradation.
基金the German Research Society Deutsche Forschungsgesellschaft(Forschergruppe Nanometerschichtsysteme).
文摘Mo/Si muitilayer mirrors(30 periods,doublelayer thickness 7nm)with the AZ-PF514 resist pattern whose smallest lines and spaces structure was 0.5pm were etched by reactive ion etching(RIE)in a fluorinated plasma.The etch rate,selectivity and etch profile were investigated as a function of the gas mixture,pressure,and plasma rf power.The groove depth and the etch proHle were investigated by an atomic force microscope before RIE,after RIE and after resist removal.
基金Supported by the National Natural Science Foundation of China under Grant No.69578023。
文摘The thermal and chemical stabilities of Mo/Si multilayer structure used in Bragg-Fresnel optics were studied to get optimal technological parameters of pattern generation.Mo/Si multilayers were annealed at temperature ranging from 360 to 770 K,treated with acetone and 5‰NaOH solution,and characterized by small-angle x-ray diffraction technique as well as x-ray photoelectron spectroscopy and Olympus microscopy.
文摘By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence of the multilayer changed to zigzag layered structure at 478 K (=Tzig). Finally, the zigzag structure transformed to Au nanoparticles at 508 K. The distribution of the Au nanoparticles was random within the thin film. In situ X-ray diffraction during heating can clarify partial crystallization Si (c-Si) in the multilayer at 450 K (= ), which corresponds to metal induced crystallization (MIC) from amorphous Si (a-Si) accompanying by Au diffusion. On further heating, a-Au started to crystallize at around 480 K (=Tc) and gradually grew up to 3.2 nm in radius, although the volume of c-Si was almost constant. Continuous heating caused crystal Au (c-Au) melting into liquid AuSi (l-AuSi) at 600 K (= ), which was lower than bulk eutectic temperature ( ). Due to the AuSi eutectic effect, reversible phase transition between liquid and solid occurred once temperature is larger than . Proportionally to the maximum temperatures at each cycles (673, 873 and 1073 K), both and Au crystallization temperature approaches to . Using a thermodynamic theory of the nanoparticle formation in the eutectic system, the relationship between and the nanoparticle size is explained.
