Interfacial bonding in as deposited and annealed Co/C soft X ray multilayer structures is investigated by X ray photo electron spectroscopy (XPS).It is found that there is interdiffusion between cobalt and carbon ...Interfacial bonding in as deposited and annealed Co/C soft X ray multilayer structures is investigated by X ray photo electron spectroscopy (XPS).It is found that there is interdiffusion between cobalt and carbon in the as deposited Co/C multilayers,and this is confirmed by structure characterization using low angle X ray diffraction (LAXD).The calculation of the chemical shifts in Co C system based on Miedemas macroscopic atom model suggests that it is impossible to detect the chemical shift experimentally in the Co C compound,which is consistent with the XPS results.The presence of metallic carbide bonding is evidenced through the nature of the carbon bonding in survey taken at Co C and C Co interfaces of annealed samples.Our results also indicate that XPS is a direct method to probe the chemical bonding at the interfaces.展开更多
The observation of structural changes in multilayers （MLs） has been used to study the interaction of materials at interface under nonequilibrium conditions, and to measure atomic diffusion rate and activation energi...The observation of structural changes in multilayers （MLs） has been used to study the interaction of materials at interface under nonequilibrium conditions, and to measure atomic diffusion rate and activation energies for compound formation. Cook and Hilliard have developed a technique which allows the measurement of small interdiffusivities down to 10<sup>-27</sup>m<sup>2</sup>·s<sup>-1</sup> by X-ray diffraction. Previous measurements are concentrated mainly on the crystalline metallic multilayers and amorphous metallic multilayers. To our knowledge, few interdiffusion measurements have been carried out for amorphous metallic-metalloid multilayers. As effective soft X-ray mirrors, Co/C multilayers have been successfully used in an X-ray telescope. Therefore, this note aims to report the interdiffusion of sputtered展开更多
The structural stability of heat-treated CoN/CN soft X-ray multilayers fabricated by dual-facing-target sputtering has been investigated by using complementary measurement techniques.The high temperature annealing res...The structural stability of heat-treated CoN/CN soft X-ray multilayers fabricated by dual-facing-target sputtering has been investigated by using complementary measurement techniques.The high temperature annealing results imply that the destructive threshold of the Co/C multilayers is improved by 100-200 degrees centigrade through doping with N.The low-angle X-ray diffraction of CoN/CN soft X-ray multilayers indicates that the period expansion of the multilayers is only 4 % at 400℃,and the interface pattern still exists even if they were annealed at 700℃.The Raman spectra analyses give the evidence that the formation of the sp bonding in the CN sublayers can be suppressed effectively by doping N with atoms,and thus the period expansion resulting from the changes in the density of CN layers can be decreased considerably.The X-ray photoelectron spectra analyses present the information of the existence of the strong covalent bonding between C and N atoms,and the ionic bonding between Co and N atoms,which can slow down the tendency of the structural relaxation.The interstitial N atoms decrease the mobility of Co atoms,and thus the fee-Co and hep-Co coexist even though the annealing temperature is much higher than the phase transformation temperature of 420℃,leading to the suppression of the grain growth.展开更多
文摘Interfacial bonding in as deposited and annealed Co/C soft X ray multilayer structures is investigated by X ray photo electron spectroscopy (XPS).It is found that there is interdiffusion between cobalt and carbon in the as deposited Co/C multilayers,and this is confirmed by structure characterization using low angle X ray diffraction (LAXD).The calculation of the chemical shifts in Co C system based on Miedemas macroscopic atom model suggests that it is impossible to detect the chemical shift experimentally in the Co C compound,which is consistent with the XPS results.The presence of metallic carbide bonding is evidenced through the nature of the carbon bonding in survey taken at Co C and C Co interfaces of annealed samples.Our results also indicate that XPS is a direct method to probe the chemical bonding at the interfaces.
基金Project supported by the National Natural Science Foundation of ChinaBeijing Zhongguancun Associated Center of AnalysisMeasurement.
文摘The observation of structural changes in multilayers （MLs） has been used to study the interaction of materials at interface under nonequilibrium conditions, and to measure atomic diffusion rate and activation energies for compound formation. Cook and Hilliard have developed a technique which allows the measurement of small interdiffusivities down to 10<sup>-27</sup>m<sup>2</sup>·s<sup>-1</sup> by X-ray diffraction. Previous measurements are concentrated mainly on the crystalline metallic multilayers and amorphous metallic multilayers. To our knowledge, few interdiffusion measurements have been carried out for amorphous metallic-metalloid multilayers. As effective soft X-ray mirrors, Co/C multilayers have been successfully used in an X-ray telescope. Therefore, this note aims to report the interdiffusion of sputtered
基金Project supported by the National Natural Science Foundation of China and Beijing Zhongguancun Associated Center of Analysis and Measurement.
文摘The structural stability of heat-treated CoN/CN soft X-ray multilayers fabricated by dual-facing-target sputtering has been investigated by using complementary measurement techniques.The high temperature annealing results imply that the destructive threshold of the Co/C multilayers is improved by 100-200 degrees centigrade through doping with N.The low-angle X-ray diffraction of CoN/CN soft X-ray multilayers indicates that the period expansion of the multilayers is only 4 % at 400℃,and the interface pattern still exists even if they were annealed at 700℃.The Raman spectra analyses give the evidence that the formation of the sp bonding in the CN sublayers can be suppressed effectively by doping N with atoms,and thus the period expansion resulting from the changes in the density of CN layers can be decreased considerably.The X-ray photoelectron spectra analyses present the information of the existence of the strong covalent bonding between C and N atoms,and the ionic bonding between Co and N atoms,which can slow down the tendency of the structural relaxation.The interstitial N atoms decrease the mobility of Co atoms,and thus the fee-Co and hep-Co coexist even though the annealing temperature is much higher than the phase transformation temperature of 420℃,leading to the suppression of the grain growth.
