To increase the low-field magnetostriction of TbFe films, the influences of sputtering angles and annealing temperatures on its magnetic and magnetostrictive performances were systematically investigated. With the cha...To increase the low-field magnetostriction of TbFe films, the influences of sputtering angles and annealing temperatures on its magnetic and magnetostrictive performances were systematically investigated. With the change in sputtering angles from 90° to 15°, the in-plane magnetization of TbFe films, at 1600 kA·m-1 external field, is strongly increased. An enhancement in the in-plane magnetostrictive coefficient of the films at 40 kA·m-1 is also observed. A detection of magnetic domains by MFM (magnetic force microscopy) indicates that the easy magnetization direction shifts gradually from perpendicular to parallel to the film plane with decreasing sputtering angles. Annealing can enhance the magnetization and magnetostriction of the TbFe films. However, at too high annealing temperature, both the magnetization and magnetostriction of the TbFe films were suppressed to some extent.展开更多
Exchange coupling multilayer thin films, which combined giant magnetostriction and soft magnetic properties, were of growing interest for applications. The TbFe/FeAl multilayer thin films were prepared by dc magnetron...Exchange coupling multilayer thin films, which combined giant magnetostriction and soft magnetic properties, were of growing interest for applications. The TbFe/FeAl multilayer thin films were prepared by dc magnetron sputtering onto glass substrates. The microstructure, magnetic, and magnetostrictive properties of TbFe/FeAl multilayer thin film was investigated at different annealing temperatures. The results indicated that the soft magnetic and magnetostrictive properties for TbFe/FeAlmultilayer thin film compared with TbFe single layer film were obviously improved./n comparison with the intrinsic coercivity JHo of 59.2 kA/m for TbFe single layer film, the intrinsic coercivity jHc for TbFe/FeAl multilayer thin films rapidly dropped to 29.6 kA/m. After optimal annealing （350 ℃×60 min）, magnetic properties of Hs=96 kA/m and jHc=16 kA/m were obtained, and magnetostrictive coefficient could reach to 574×10^-6 under an external magnetic field of 400 kA·m^-1 for the TbFe/FeA1 multilayer thin film.展开更多
The pure TbFe 2 is a sort of intermetallic compound to produce (TbDy)Fe 2. It has important practical meanings to develop a new method for producing pure TbFe 2 directly from Tb 4O 7 with low cost and non pollu...The pure TbFe 2 is a sort of intermetallic compound to produce (TbDy)Fe 2. It has important practical meanings to develop a new method for producing pure TbFe 2 directly from Tb 4O 7 with low cost and non pollution. Based on our previous thermodynamic study on the production of TbFe 2 by reduction diffusion in Ca Tb 4O 7 Fe system, kinetics has been further studied in this work. It is confirmed that the product is TbFe 2 by means of XRD. The contracting core model is applied. The reactions are found to be diffusion controlled. The apparent activation energy of TbFe 2 is 39 kJ·mol -1 .展开更多
The exchange-coupled [Co/Ni]N/Tb Fe nano-magnetic films can display strong perpendicular magnetic anisotropy(PMA) which depends on the Tb:Fe component ratio, Tb Fe layer thickness and the repetition number N of [Co/Ni...The exchange-coupled [Co/Ni]N/Tb Fe nano-magnetic films can display strong perpendicular magnetic anisotropy(PMA) which depends on the Tb:Fe component ratio, Tb Fe layer thickness and the repetition number N of [Co/Ni]Nmultilayer. Perpendicular spin valves in the nano thickness scale, consisting of a [Co/Ni]3free and a [Co/Ni]5/Tb Fe reference multilayer, show high giant magnetoresistance(GMR) signal of 6.5 % and a large switching field difference over3 k Oe. However, unexpected slanting of the free layer magnetization, accompanied by a reduced GMR ratio, was found to be caused by the presence of a thick Fe-rich or even a thin but Tb-rich Tb Fe layer. We attribute this phenomenon to the large magnetostriction effect of Tb Fe which probably induces strong stress acting on the free layer and hence reduces its interfacial PMA.展开更多
The pure intermetallic compounds (Tb1-x;Dyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2 and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and...The pure intermetallic compounds (Tb1-x;Dyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2 and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and TbFe2 preparation by reduction-diffusion in Ca-Dy2O3-Fe and Ca-Tb4O7-Fe systems were analyzed and the products of DyFe2 and TbFe2 were confirmed by XRD. The contracting core model was applied to describe the reduction-diffusion process in which the diffusion is a rate-controlled step. The apparent activation energies of DyFe2 and TbFe2 processes are 45 and 39 kJ/mol respectively.展开更多
基金We are grateful to the National Natural Science Foundation of China(Grant No.50271014)for the financial support of this work.
文摘To increase the low-field magnetostriction of TbFe films, the influences of sputtering angles and annealing temperatures on its magnetic and magnetostrictive performances were systematically investigated. With the change in sputtering angles from 90° to 15°, the in-plane magnetization of TbFe films, at 1600 kA·m-1 external field, is strongly increased. An enhancement in the in-plane magnetostrictive coefficient of the films at 40 kA·m-1 is also observed. A detection of magnetic domains by MFM (magnetic force microscopy) indicates that the easy magnetization direction shifts gradually from perpendicular to parallel to the film plane with decreasing sputtering angles. Annealing can enhance the magnetization and magnetostriction of the TbFe films. However, at too high annealing temperature, both the magnetization and magnetostriction of the TbFe films were suppressed to some extent.
基金the Shanghai Municipal Nature Science Foundation (05NZ03)the Leading Academic Discipline Project of the Shang-hai Education Commission, China (XK0706)
文摘Exchange coupling multilayer thin films, which combined giant magnetostriction and soft magnetic properties, were of growing interest for applications. The TbFe/FeAl multilayer thin films were prepared by dc magnetron sputtering onto glass substrates. The microstructure, magnetic, and magnetostrictive properties of TbFe/FeAl multilayer thin film was investigated at different annealing temperatures. The results indicated that the soft magnetic and magnetostrictive properties for TbFe/FeAlmultilayer thin film compared with TbFe single layer film were obviously improved./n comparison with the intrinsic coercivity JHo of 59.2 kA/m for TbFe single layer film, the intrinsic coercivity jHc for TbFe/FeAl multilayer thin films rapidly dropped to 29.6 kA/m. After optimal annealing （350 ℃×60 min）, magnetic properties of Hs=96 kA/m and jHc=16 kA/m were obtained, and magnetostrictive coefficient could reach to 574×10^-6 under an external magnetic field of 400 kA·m^-1 for the TbFe/FeA1 multilayer thin film.
文摘The pure TbFe 2 is a sort of intermetallic compound to produce (TbDy)Fe 2. It has important practical meanings to develop a new method for producing pure TbFe 2 directly from Tb 4O 7 with low cost and non pollution. Based on our previous thermodynamic study on the production of TbFe 2 by reduction diffusion in Ca Tb 4O 7 Fe system, kinetics has been further studied in this work. It is confirmed that the product is TbFe 2 by means of XRD. The contracting core model is applied. The reactions are found to be diffusion controlled. The apparent activation energy of TbFe 2 is 39 kJ·mol -1 .
基金supported by the National Basic Research Program of China (2014CB921104)the National Natural Science Foundation of China (Grant Nos. 51222103, 11274113, 11474067, and 51171047)the support from the Program for New Century Excellent Talents in University (NCET-12-0132)
文摘The exchange-coupled [Co/Ni]N/Tb Fe nano-magnetic films can display strong perpendicular magnetic anisotropy(PMA) which depends on the Tb:Fe component ratio, Tb Fe layer thickness and the repetition number N of [Co/Ni]Nmultilayer. Perpendicular spin valves in the nano thickness scale, consisting of a [Co/Ni]3free and a [Co/Ni]5/Tb Fe reference multilayer, show high giant magnetoresistance(GMR) signal of 6.5 % and a large switching field difference over3 k Oe. However, unexpected slanting of the free layer magnetization, accompanied by a reduced GMR ratio, was found to be caused by the presence of a thick Fe-rich or even a thin but Tb-rich Tb Fe layer. We attribute this phenomenon to the large magnetostriction effect of Tb Fe which probably induces strong stress acting on the free layer and hence reduces its interfacial PMA.
文摘The pure intermetallic compounds (Tb1-x;Dyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2 and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and TbFe2 preparation by reduction-diffusion in Ca-Dy2O3-Fe and Ca-Tb4O7-Fe systems were analyzed and the products of DyFe2 and TbFe2 were confirmed by XRD. The contracting core model was applied to describe the reduction-diffusion process in which the diffusion is a rate-controlled step. The apparent activation energies of DyFe2 and TbFe2 processes are 45 and 39 kJ/mol respectively.
