Ag/Fe multilayers with well compositional modulation periodicity of 4-60 nm were prepared at room temperature by evaporation deposition using an ultra high vacuum (UHV) chamber. Their microstructure and hardness were ...Ag/Fe multilayers with well compositional modulation periodicity of 4-60 nm were prepared at room temperature by evaporation deposition using an ultra high vacuum (UHV) chamber. Their microstructure and hardness were investigated using XRD, TEM and nanoindentation. The fcc/bcc type multilayers show a textured polycrystalline growth with Ag (111) and Fe (110) in Ag layers and Fe layers, respectively. The hardness increases with decreasing periodicity and approaches the maximum of 6.36 GPa at the periodicity of 4 nm. The peak hardness is 1.51 times mixture value. The experimental results are well explained by the dislocation-image force-based model developed by Lehoczky.展开更多
The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO_(4)(LFP)/graphite batteries;there is a lack of systematic under...The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO_(4)(LFP)/graphite batteries;there is a lack of systematic understanding of the spatial distribution of the EEI interface layer and the dissolve of Fe ions,especially in terms of the mechanism of the cathode-electrolyte interphase(CEI),solid electrolyte interphase(SEI),and iron dissolution.In this study,aged cells were subjected to continuous activation with constant current and multi-step segmented indirect activation(IA)and analyzed for capacity fade,impedance growth,and active Li^(+)mass loss at the EEI and nanoscale levels.The interaction between dissolved Fe^(2+)and the EEI in LFP/graphite pouch batteries was proposed and verified.The findings indicate that during IA process,the electric field facilitates the migration of solvated ions toward the electrodes,while simultaneously inhibiting the formation of organic species such as ROCO_(2)Li.The SEI primarily consists of a mixture of organic and inorganic small molecules,forming a continuous and uniform film on the electrode surface.This study demonstrates that IA favors the formation of a uniform EEI and offers constructive insights for advancing accelerated lifetime prediction strategies in lithium-ion batteries.展开更多
[FePt/Ag]n multilayers were deposited on glass substrates by RF magnetron sputtering and ex situ annealed at 550℃ for 30 min. The effects of inserted Ag layer thickness and the number of bilayer repetitions （n） on ...[FePt/Ag]n multilayers were deposited on glass substrates by RF magnetron sputtering and ex situ annealed at 550℃ for 30 min. The effects of inserted Ag layer thickness and the number of bilayer repetitions （n） on the structure and magnetic properties of the multilayers were investigated. It was found that the difference between in-plane and out-of-plane coercivities varied with an increase of inserted Ag layer thickness in the [FePt 2 nm/Ag x nm]10 multilayers. The ratio of out-of-plane coercivity to in-plane coercivity reached the maximum value with the Ag layer thickness of 5 nm, indicating that the Ag layer thickness plays an important role in obtaining perpendicular orientation. For the [FePt 2 nm/Ag 5 um]n multilayers, perpendicular orientation is also influenced by n. The maximum value of the ratio of out-of-plane coercivity to in-plane coercivity appeared when n was given as 8. It was found that the [FePt 2 nm/Ag 5 nm]8 had a high perpendicular coercivity of 520 kA/m and a low in-plane one of 88 kA/m, which shows a strong perpendicular anisotropy.展开更多
Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensi...Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensional(1D)micromagnetic methods,focused on the influence of the interface anisotropy.The calculated results are carefully compared with each other.The interface anisotropy effect is very palpable on the nucleation,pinning and coercive fields when the soft layer is very thin.However,as the soft layer thickness increases,the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically rises.Negative interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied field.The magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal,i.e.,nucleation,evolution and irreversible motion of the domain wall.The above results calculated by two models are in good agreement with each other.Moreover,the in-plane magnetic moment orientations based on two models are different.The 3D calculation shows a progress of generation and disappearance of vortex state,however,the magnetization orientations within the film plane calculated by the 1D model are coherent.Simulation results suggest that negative interface anisotropy is necessarily avoided experimentally.展开更多
Magnetic properties and microstructure of Fe/RE multilayers(thickness of Fe single layers less than or equal to 2.0 nm) both as-deposited state and after annealing( T greater than or equal to 473 K) were studied, and ...Magnetic properties and microstructure of Fe/RE multilayers(thickness of Fe single layers less than or equal to 2.0 nm) both as-deposited state and after annealing( T greater than or equal to 473 K) were studied, and the reason of the change of magnetic properties was analyzed. The Fe single layers are considered to be composed of insular Fe domains in as-deposited films. Super-paramagnetic nature of the Fe domains of small size causes the films to exhibit paramagnetism. During annealing the growth of Fe domains results in the transformation of films from paramagnetic into ferromagnetic, which leads to the increase in H-c and M-s.展开更多
The composition, phase structure, and microstructure of the discontinuous multilayer films [NiFeCo(10 nm)/ Ag(10 nm)]×20 annealed at temperature 280, 320, 360 and 400℃, respectively were investigated. GMR (giant...The composition, phase structure, and microstructure of the discontinuous multilayer films [NiFeCo(10 nm)/ Ag(10 nm)]×20 annealed at temperature 280, 320, 360 and 400℃, respectively were investigated. GMR (giant magnetore-sistance) ratios of the multilayer films were measured at different temperatures. The results showed that FeNi3 precipitated at 360℃ and dissolved at 400℃. The films annealed at 360℃ for 1 h exhibited the highest GMR ratio 11% when saturation field was equal to 79.6 kA/m.展开更多
The one-dimensional photonic crystals of Ag/SiO_(2) system are studied to investigate the photonic band gaps (PBG). The samples were prepared by the ultra-high vacuum electron beam evaporation. The clear band gaps wer...The one-dimensional photonic crystals of Ag/SiO_(2) system are studied to investigate the photonic band gaps (PBG). The samples were prepared by the ultra-high vacuum electron beam evaporation. The clear band gaps were observed. Satisfactory agreement between experimental and calculated results was obtained without fitting. The thickness of SiO_(2 )film has influence on the photonic band gap, as well as it awfully affects the transmittance of Ag. More layers can get clearer PBG.展开更多
Self-designed Al8Si0.4Mg0.4Fe aluminium alloy was modified with Sr,followed by solid solution and aging treatments to regulate its microstructure and mechanical/electrical properties.The results show that after the mo...Self-designed Al8Si0.4Mg0.4Fe aluminium alloy was modified with Sr,followed by solid solution and aging treatments to regulate its microstructure and mechanical/electrical properties.The results show that after the modification treatment,the room-temperature tensile strength of the alloy remains nearly unchanged,the elongation at break slightly increases from 1.82%to 3.34%,and the electrical conductivity significantly increases from 40.1%international annealed copper standard(IACS)to 42.0%IACS.After the modification,the alloy was subjected to solid solution treatment at 515℃for 8 h,followed by aging treatment at 180,200,220 and 240℃for 6 h.With increasing aging temperature,the electrical conductivity increases monotonously from 41.4%IACS to 45.5%IACS,while the room-temperature tensile strength initially increases and then decreases.At 200℃,the alloy achieves an optimal balance between electrical conductivity and room-temperature tensile strength:the electrical conductivity is 42.5%IACS,and the room-temperature tensile strength is 282.9 MPa.When the aging temperature continues to rise,the alloy undergoes overaging.Although the conductivity continues to increase,the room-temperature tensile strength drops sharply,and it is only 177.1 MPa at 240℃.展开更多
The plastic deformation mechanism of Cu/Ag multilayers is investigated by molecular dynamics （MD） simulation in a nanoindentation process. The result shows that due to the interface barrier, the dislocations pile-up...The plastic deformation mechanism of Cu/Ag multilayers is investigated by molecular dynamics （MD） simulation in a nanoindentation process. The result shows that due to the interface barrier, the dislocations pile-up at the interface and then the plastic deformation of the Ag matrix occurs due to the nucleation and emission of dislocations from the interface and the dislocation propagation through the interface. In addition, it is found that the incipient plastic deformation of Cu/Ag multilayers is postponed, compared with that of bulk single-crystal Cu. The plastic deformation of Cu/Ag multilayers is affected by the lattice mismatch more than by the difference in stacking fault energy （SFE） between Cu and Ag. The dislocation pile-up at the interface is determined by the obstruction of the mismatch dislocation network and the attraction of the image force. Furthermore, this work provides a basis for further understanding and tailoring metal multilayers with good mechanical properties, which may facilitate the design and development of multilayer materials with low cost production strategies.展开更多
Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opport...Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opportunities for exploring novel topological phenomena and fascinating applications.Utilizing a low-temperature scanning tunneling microscope,we construct breathing-kagome lattices with Fe adatoms on Ag(111)and investigate their electronic properties.We observe the higher-order topological boundary states in the topological phase but not in the trivial one,which is consistent with the theory.These states are found to be robust against the removal of bulk or edge adatoms.Further,we show the arbitrary positioning of these states either at corner,edge,or bulk sites by slightly modifying their neighbors.Our study not only demonstrates the formation and robustness of the electronic higher-order topological boundary states in real atomic systems but also provides a route for controlling their positions.展开更多
RE/Fe multilayer films were prepared by alternate deposition of the two elements onto Si or NaCl single crystal substrates(RE=Dy, Y). The changes in structure of the films were analyzed in situ on the transmission ele...RE/Fe multilayer films were prepared by alternate deposition of the two elements onto Si or NaCl single crystal substrates(RE=Dy, Y). The changes in structure of the films were analyzed in situ on the transmission electron microscope(TEM) hot stage, and were studied by Xray diffraction(XRD) after annealing under vacuum. It was found that, annealing at temperature≤200 ℃ for a long time(～300 min), the amorphous state and the modulated structure of asdeposited films remained basically unchanged. It is suggested that RE/Fe multilayers are stable at temperature up to 200 ℃.〖HS*2]展开更多
The composition, phase structure and microstructure of the discontinuous multilayer film[NiFeCo（10 nm）/Ag（10 nm）]×20 were investigated after Co ion implantation and annealing at 280, 320,360 and 400℃, respec...The composition, phase structure and microstructure of the discontinuous multilayer film[NiFeCo（10 nm）/Ag（10 nm）]×20 were investigated after Co ion implantation and annealing at 280, 320,360 and 400℃, respectively.GMR （giant magnetoresistance） ratio of the film with/without Co ion implantation was measured. The results showed that Co ion implantation decreased the granule size of the annealed multilayer film, and increased Hc value and GMR ratio of the multilayer film. After annealing at 360℃, the multilayer film [NiFeCo（10 nm）/Ag（10 nm）]×20 with/without Co ion implantation both exhibited the highest GMR ratio of 12.4%/11% under 79.6 kA/m of applied saturation magnetic field.展开更多
Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar st...Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction; for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.展开更多
Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation ...Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation agrees well with that determined from deposition rate. The interfacial roughness parameter ξof several samples calculated by X-ray diffraction is between 3.5(?) and 5.6(?).展开更多
基金Projects(50871060, 50772055) supported by the National Natural Science Foundation of ChinaProject(2007AA03Z426) supported by High-tech Research and Development Program of China
文摘Ag/Fe multilayers with well compositional modulation periodicity of 4-60 nm were prepared at room temperature by evaporation deposition using an ultra high vacuum (UHV) chamber. Their microstructure and hardness were investigated using XRD, TEM and nanoindentation. The fcc/bcc type multilayers show a textured polycrystalline growth with Ag (111) and Fe (110) in Ag layers and Fe layers, respectively. The hardness increases with decreasing periodicity and approaches the maximum of 6.36 GPa at the periodicity of 4 nm. The peak hardness is 1.51 times mixture value. The experimental results are well explained by the dislocation-image force-based model developed by Lehoczky.
基金supported by the National Key R&D Program of China(2021YFB2401800)the support from Beijing Nova Program(20230484241)+2 种基金the support from the China Postdoctoral Science Foundation(2024M754084)the Postdoctoral Fellowship Program of CPSF(GZB20230931)the support from Initial Energy Science&Technology Co.,Ltd(IEST)。
文摘The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO_(4)(LFP)/graphite batteries;there is a lack of systematic understanding of the spatial distribution of the EEI interface layer and the dissolve of Fe ions,especially in terms of the mechanism of the cathode-electrolyte interphase(CEI),solid electrolyte interphase(SEI),and iron dissolution.In this study,aged cells were subjected to continuous activation with constant current and multi-step segmented indirect activation(IA)and analyzed for capacity fade,impedance growth,and active Li^(+)mass loss at the EEI and nanoscale levels.The interaction between dissolved Fe^(2+)and the EEI in LFP/graphite pouch batteries was proposed and verified.The findings indicate that during IA process,the electric field facilitates the migration of solvated ions toward the electrodes,while simultaneously inhibiting the formation of organic species such as ROCO_(2)Li.The SEI primarily consists of a mixture of organic and inorganic small molecules,forming a continuous and uniform film on the electrode surface.This study demonstrates that IA favors the formation of a uniform EEI and offers constructive insights for advancing accelerated lifetime prediction strategies in lithium-ion batteries.
基金This work is financially supported by the National Natural Science Foundation of China (No. 10574085) Natural Science Foundation ofShanxi Province, China (No. 20041032).
文摘[FePt/Ag]n multilayers were deposited on glass substrates by RF magnetron sputtering and ex situ annealed at 550℃ for 30 min. The effects of inserted Ag layer thickness and the number of bilayer repetitions （n） on the structure and magnetic properties of the multilayers were investigated. It was found that the difference between in-plane and out-of-plane coercivities varied with an increase of inserted Ag layer thickness in the [FePt 2 nm/Ag x nm]10 multilayers. The ratio of out-of-plane coercivity to in-plane coercivity reached the maximum value with the Ag layer thickness of 5 nm, indicating that the Ag layer thickness plays an important role in obtaining perpendicular orientation. For the [FePt 2 nm/Ag 5 um]n multilayers, perpendicular orientation is also influenced by n. The maximum value of the ratio of out-of-plane coercivity to in-plane coercivity appeared when n was given as 8. It was found that the [FePt 2 nm/Ag 5 nm]8 had a high perpendicular coercivity of 520 kA/m and a low in-plane one of 88 kA/m, which shows a strong perpendicular anisotropy.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0700900)the National Natural Science Foundation of China(Grant Nos.51571126 and 51861030)+1 种基金the Inner Mongolia Autonomous Region Natural Science Foundation of China(Grant No.2019MS01002)the Inner Mongolia Innovative Research Team of China(Grant No.3400102)。
文摘Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensional(1D)micromagnetic methods,focused on the influence of the interface anisotropy.The calculated results are carefully compared with each other.The interface anisotropy effect is very palpable on the nucleation,pinning and coercive fields when the soft layer is very thin.However,as the soft layer thickness increases,the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically rises.Negative interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied field.The magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal,i.e.,nucleation,evolution and irreversible motion of the domain wall.The above results calculated by two models are in good agreement with each other.Moreover,the in-plane magnetic moment orientations based on two models are different.The 3D calculation shows a progress of generation and disappearance of vortex state,however,the magnetization orientations within the film plane calculated by the 1D model are coherent.Simulation results suggest that negative interface anisotropy is necessarily avoided experimentally.
文摘Magnetic properties and microstructure of Fe/RE multilayers(thickness of Fe single layers less than or equal to 2.0 nm) both as-deposited state and after annealing( T greater than or equal to 473 K) were studied, and the reason of the change of magnetic properties was analyzed. The Fe single layers are considered to be composed of insular Fe domains in as-deposited films. Super-paramagnetic nature of the Fe domains of small size causes the films to exhibit paramagnetism. During annealing the growth of Fe domains results in the transformation of films from paramagnetic into ferromagnetic, which leads to the increase in H-c and M-s.
基金This work was supported by the National Natural Science Foundation of China under grant No.59771026.
文摘The composition, phase structure, and microstructure of the discontinuous multilayer films [NiFeCo(10 nm)/ Ag(10 nm)]×20 annealed at temperature 280, 320, 360 and 400℃, respectively were investigated. GMR (giant magnetore-sistance) ratios of the multilayer films were measured at different temperatures. The results showed that FeNi3 precipitated at 360℃ and dissolved at 400℃. The films annealed at 360℃ for 1 h exhibited the highest GMR ratio 11% when saturation field was equal to 79.6 kA/m.
基金Supported by the National High Technology Development Program of China(Grant No.2003AA32720)Shanghai Nanotechnology Promotion Center(0352nm016, 0359nm204,0252nm084)+2 种基金Science and Technology Council of Shanghai(03dz11009)Fore-research of basic research project(2001CCA02800)the special Foundation for State Major Basic Research Programmeof China(Grant No.001CB610408)
文摘The one-dimensional photonic crystals of Ag/SiO_(2) system are studied to investigate the photonic band gaps (PBG). The samples were prepared by the ultra-high vacuum electron beam evaporation. The clear band gaps were observed. Satisfactory agreement between experimental and calculated results was obtained without fitting. The thickness of SiO_(2 )film has influence on the photonic band gap, as well as it awfully affects the transmittance of Ag. More layers can get clearer PBG.
基金Applied Basic Research Program of Liaoning Province(CN)(2022JH2/101300078)。
文摘Self-designed Al8Si0.4Mg0.4Fe aluminium alloy was modified with Sr,followed by solid solution and aging treatments to regulate its microstructure and mechanical/electrical properties.The results show that after the modification treatment,the room-temperature tensile strength of the alloy remains nearly unchanged,the elongation at break slightly increases from 1.82%to 3.34%,and the electrical conductivity significantly increases from 40.1%international annealed copper standard(IACS)to 42.0%IACS.After the modification,the alloy was subjected to solid solution treatment at 515℃for 8 h,followed by aging treatment at 180,200,220 and 240℃for 6 h.With increasing aging temperature,the electrical conductivity increases monotonously from 41.4%IACS to 45.5%IACS,while the room-temperature tensile strength initially increases and then decreases.At 200℃,the alloy achieves an optimal balance between electrical conductivity and room-temperature tensile strength:the electrical conductivity is 42.5%IACS,and the room-temperature tensile strength is 282.9 MPa.When the aging temperature continues to rise,the alloy undergoes overaging.Although the conductivity continues to increase,the room-temperature tensile strength drops sharply,and it is only 177.1 MPa at 240℃.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11572118 and 11372103)the Hunan Provincial Science Fund for Distinguished Young Scholars,China(Grant No.2015JJ1006)the National Key Research and Development Program of China(Grant No.2016YFB0700300)
文摘The plastic deformation mechanism of Cu/Ag multilayers is investigated by molecular dynamics （MD） simulation in a nanoindentation process. The result shows that due to the interface barrier, the dislocations pile-up at the interface and then the plastic deformation of the Ag matrix occurs due to the nucleation and emission of dislocations from the interface and the dislocation propagation through the interface. In addition, it is found that the incipient plastic deformation of Cu/Ag multilayers is postponed, compared with that of bulk single-crystal Cu. The plastic deformation of Cu/Ag multilayers is affected by the lattice mismatch more than by the difference in stacking fault energy （SFE） between Cu and Ag. The dislocation pile-up at the interface is determined by the obstruction of the mismatch dislocation network and the attraction of the image force. Furthermore, this work provides a basis for further understanding and tailoring metal multilayers with good mechanical properties, which may facilitate the design and development of multilayer materials with low cost production strategies.
基金supported by the National Key R&D Program of China(Grant Nos.2024YFA140850,2022YFA1403601,and 2023YFC2410501)the National Natural Science Foundation of China(Grants Nos.12241402,12474059,12274203,12374113,and 12274204)。
文摘Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opportunities for exploring novel topological phenomena and fascinating applications.Utilizing a low-temperature scanning tunneling microscope,we construct breathing-kagome lattices with Fe adatoms on Ag(111)and investigate their electronic properties.We observe the higher-order topological boundary states in the topological phase but not in the trivial one,which is consistent with the theory.These states are found to be robust against the removal of bulk or edge adatoms.Further,we show the arbitrary positioning of these states either at corner,edge,or bulk sites by slightly modifying their neighbors.Our study not only demonstrates the formation and robustness of the electronic higher-order topological boundary states in real atomic systems but also provides a route for controlling their positions.
文摘RE/Fe multilayer films were prepared by alternate deposition of the two elements onto Si or NaCl single crystal substrates(RE=Dy, Y). The changes in structure of the films were analyzed in situ on the transmission electron microscope(TEM) hot stage, and were studied by Xray diffraction(XRD) after annealing under vacuum. It was found that, annealing at temperature≤200 ℃ for a long time(～300 min), the amorphous state and the modulated structure of asdeposited films remained basically unchanged. It is suggested that RE/Fe multilayers are stable at temperature up to 200 ℃.〖HS*2]
基金support by the National Natural Science Foundation of China under grant No.59771026.
文摘The composition, phase structure and microstructure of the discontinuous multilayer film[NiFeCo（10 nm）/Ag（10 nm）]×20 were investigated after Co ion implantation and annealing at 280, 320,360 and 400℃, respectively.GMR （giant magnetoresistance） ratio of the film with/without Co ion implantation was measured. The results showed that Co ion implantation decreased the granule size of the annealed multilayer film, and increased Hc value and GMR ratio of the multilayer film. After annealing at 360℃, the multilayer film [NiFeCo（10 nm）/Ag（10 nm）]×20 with/without Co ion implantation both exhibited the highest GMR ratio of 12.4%/11% under 79.6 kA/m of applied saturation magnetic field.
基金Financial support from National Natural Science Foundation of China and the Ministry of Science&Technology of China(Grant No.(1999064505)is acknowledged.
文摘Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction; for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.
文摘Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation agrees well with that determined from deposition rate. The interfacial roughness parameter ξof several samples calculated by X-ray diffraction is between 3.5(?) and 5.6(?).
