The early precipitation process of Ni（75）Al（14）Mo（11） alloy was simulated by microscopic phase-field model at different temperatures.The microstructure of the alloy,the precipitation time of Llo structure and oc...The early precipitation process of Ni（75）Al（14）Mo（11） alloy was simulated by microscopic phase-field model at different temperatures.The microstructure of the alloy,the precipitation time of Llo structure and occupation probability of the three kinds of atoms were investigated.It is indicated that the non-stoichiometric Ll0（Ⅰ/Ⅱ） phases are found in the precipitation process.With the temperature increasing,the appearance time of Ll0 is brought forward.The Ll0（Ⅱ） structure always precipitates earlier than the Ll0（Ⅰ） structure.Compared with lower temperature,higher temperature brings the formation time of Ll0 phase forward and makes Ll0 phase have a higher order degree.But lower temperature shortens the process time of the Ll0 phase to the Ll2 phase.Al and Mo atoms tend to occupy γ site,Ni atom tends to occupy a and β sites.At the same temperature,Al atom has stronger occupation ability than Mo atom in the same site.Ni,Al and Mo collectively form the composited Ll2 structure.展开更多
Thin Mn（2 nm）/Al（2 nm） bilayers serving as buffer layers have been prepared prior to the deposition of MnAl films. The ferromagnetic T-phase forms in the buffer layers at an optimum substrate temperature. As a tem...Thin Mn（2 nm）/Al（2 nm） bilayers serving as buffer layers have been prepared prior to the deposition of MnAl films. The ferromagnetic T-phase forms in the buffer layers at an optimum substrate temperature. As a template it induces the growth of following MnAl film. Compared with the case of film without buffer layer, the growth of nonferromagnetic phase is suppressed and the structural and magnetic properties of MnAl film are improved. Weak dipolar inter-grain coupling is revealed in the MnAl film, and the magnetic reversal process is dominated by magnetic moment rotation.展开更多
An Si(001)/SiO2/Ti/Pt/Fe/Cu multilayer was prepared by direct-current magnetic sputtering system. The phase composition of the film was characterized by X-ray diffractometry(XRD), and the microstructure was observed b...An Si(001)/SiO2/Ti/Pt/Fe/Cu multilayer was prepared by direct-current magnetic sputtering system. The phase composition of the film was characterized by X-ray diffractometry(XRD), and the microstructure was observed by scanning electronic microscopy(SEM). Through the film annealed in magnetic field perpendicular to the surface of the film, FCC FePt film with (001) texture was obtained. And the density of the particle in the film annealed without magnetic field is very small compared with that in the film annealed with magnetic field. And the effect of magnetic field annealing on the microstructure of Fe/Pt film and the segregation of FCC FePt phase were also discussed.展开更多
基金Project(51275486)supported by the National Natural Science Foundation of China
文摘The early precipitation process of Ni（75）Al（14）Mo（11） alloy was simulated by microscopic phase-field model at different temperatures.The microstructure of the alloy,the precipitation time of Llo structure and occupation probability of the three kinds of atoms were investigated.It is indicated that the non-stoichiometric Ll0（Ⅰ/Ⅱ） phases are found in the precipitation process.With the temperature increasing,the appearance time of Ll0 is brought forward.The Ll0（Ⅱ） structure always precipitates earlier than the Ll0（Ⅰ） structure.Compared with lower temperature,higher temperature brings the formation time of Ll0 phase forward and makes Ll0 phase have a higher order degree.But lower temperature shortens the process time of the Ll0 phase to the Ll2 phase.Al and Mo atoms tend to occupy γ site,Ni atom tends to occupy a and β sites.At the same temperature,Al atom has stronger occupation ability than Mo atom in the same site.Ni,Al and Mo collectively form the composited Ll2 structure.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60490290, 60678008, 10604016, 50771032,and 50771033)the National Basic Research Program of China (Grant No. 2009CB929201)
文摘Thin Mn（2 nm）/Al（2 nm） bilayers serving as buffer layers have been prepared prior to the deposition of MnAl films. The ferromagnetic T-phase forms in the buffer layers at an optimum substrate temperature. As a template it induces the growth of following MnAl film. Compared with the case of film without buffer layer, the growth of nonferromagnetic phase is suppressed and the structural and magnetic properties of MnAl film are improved. Weak dipolar inter-grain coupling is revealed in the MnAl film, and the magnetic reversal process is dominated by magnetic moment rotation.
文摘An Si(001)/SiO2/Ti/Pt/Fe/Cu multilayer was prepared by direct-current magnetic sputtering system. The phase composition of the film was characterized by X-ray diffractometry(XRD), and the microstructure was observed by scanning electronic microscopy(SEM). Through the film annealed in magnetic field perpendicular to the surface of the film, FCC FePt film with (001) texture was obtained. And the density of the particle in the film annealed without magnetic field is very small compared with that in the film annealed with magnetic field. And the effect of magnetic field annealing on the microstructure of Fe/Pt film and the segregation of FCC FePt phase were also discussed.
