This paper reports that Eu-doped ZnO films were successfully deposited on silicon （100） by radio-frequency magnetic sputtering. The x-ray diffraction patterns indicate that Eu substitutes for Zn in the lattice. Ferr...This paper reports that Eu-doped ZnO films were successfully deposited on silicon （100） by radio-frequency magnetic sputtering. The x-ray diffraction patterns indicate that Eu substitutes for Zn in the lattice. Ferromagnetic loops were obtained by using superconducting quantum interference device at 10 K and room temperature. No discontinuous change was found in both of the zero-field-cooled and field-cooled curves. The observed ferromagnetism in Eu-doped ZnO can be attributed to a single magnetic phase. The saturation magnetisation decreased remarkably for the Eu-doped ZnO prepared by introducing 5% of oxygen in the sputtering gas or by the post annealing in O2, suggesting that the defects play key roles in the development of ferromagnetism in Eu-doped ZnO films.展开更多
La0.9Sr0.1Ga0.8Mg0.2O3–？ （LSGM） electrolyte materials were synthesized by the solid state reaction method. The conductivity of LSGM materials was detected by four probe method, and it was 0.08 S/cm at 850 oC. Dens...La0.9Sr0.1Ga0.8Mg0.2O3–？ （LSGM） electrolyte materials were synthesized by the solid state reaction method. The conductivity of LSGM materials was detected by four probe method, and it was 0.08 S/cm at 850 oC. Dense and uniform films of LSGM materials were deposited by the magnetic sputtering on substrates of Si and La0.7Sr0.3Cr0.5Mn0.5O3–？ （LSCM）. The experimental results showed that the deposition rates dropped and the average grain sizes of the films enlarged with increase in the substrate temperatures. In the sputtering process, the LSGM film was deposited with preferred growth direction. After annealing, the preferred growth direction disappeared and the film surface became smoother and denser. Through observing the deposition process, deposition mechanism was proposed, which was consistent with a model of island growth.展开更多
Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have bee...Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have been formed by a multi-step deposition and natural oxidization of Mg layer. Mg layer thickness,oxygen flow rate and oxidization time were adjusted and the tunnel magnetoresistance(TMR) ratio of optimal MTJs is over 60% at annealing temperature 385. The(001) MgO crystal structure was obtained when the separation distance between MgO target and substrate is less than 6 cm. The TMR ratio of most MgO based MTJs are over 100% at the separation distance of 5 cm and annealing temperature 340. The TMR ratios of MTJs are almost zero when the separation distance ranges from 6 to 10 cm, due to the amorphous nature of the MgO film.展开更多
Fe-N films were prepared on Si substrate by dual ion beam sputtering (DIBS). It is found that the crystal structure of the films varies from α-Fe, to ε-Fe2-3N, ε-Fe2-3N +γ-Fe4N, and finally γ'-Fe4N with the i...Fe-N films were prepared on Si substrate by dual ion beam sputtering (DIBS). It is found that the crystal structure of the films varies from α-Fe, to ε-Fe2-3N, ε-Fe2-3N +γ-Fe4N, and finally γ'-Fe4N with the increase in substrate temperature (TS). The magnetic properties of the films were investigated by a vibrating sample magnetometer (VSM). The structure of the films is insensitive to the ratios of N2/Ar in main ion source(MIS), and is mainly influenced by the substrate temperature (Ts).展开更多
The isothermal and cyclic oxidation behaviors of bulk pure nickel and its magnetically sputtered Ni 0 5Y micro crystal coating were studied at 1?000?℃ in air. Scanning electronic microscopy (SEM) and transmiss...The isothermal and cyclic oxidation behaviors of bulk pure nickel and its magnetically sputtered Ni 0 5Y micro crystal coating were studied at 1?000?℃ in air. Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine structures of the coating and the NiO oxide films. Laser Raman spectrum was also used to measure the stress level in NiO films formed on bulk nickel and the coating. It was found that Ni 0 5Y micro crystal coating had lower oxidation rate, and the grain size of NiO formed on Ni 0 5Y coating was also relatively smaller than that formed on bulk nickel. Meanwhile, the compressive stress level of oxide film formed on Ni 0 5Y coating was lower than that formed on bulk nickel, and the oxide film’s high temperature plasticity was improved in the coating case. The improvements of anti oxidation properties of the sputtered Ni 0 5Y coating were due to the micro crystal structure and the rare earth element Y.展开更多
Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si（100） substrates,and subsequently annealed in vacuum at different temperatures for different time.It is found that both the thickness of ...Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si（100） substrates,and subsequently annealed in vacuum at different temperatures for different time.It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films.Interestingly,the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film.The high coercivity of 24.1 kOe（1 Oe = 79.5775 A/m） and remanence ratio（remanent magnetization/saturation magnetization）of 0.94 can be obtained in a Ta/Nd（250 nm）/NdFeB（600 nm）/Nd（250 nm）/Ta film annealed for 3 min at 1023 K.In addition,the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well.The excellent thermal stability can be achieved in a Ta/Nd（250 nm）/NdFeB（600 nm）/Nd（250 nm）/Ta film annealed at1023 K.展开更多
High resistance thin film chip resistors(0603 type) were studied,and the specifications are as follows:1 k? with tolerance about ±0.1% after laser trimming and temperature coefficient of resistance(TCR) less than...High resistance thin film chip resistors(0603 type) were studied,and the specifications are as follows:1 k? with tolerance about ±0.1% after laser trimming and temperature coefficient of resistance(TCR) less than ±15×10-6/℃.Cr-Si-Ta-Al films were prepared with Ar flow rate and sputtering power fixed at 20 standard-state cubic centimeter per minute(sccm) and 100 W,respectively.The experiment shows that the electrical properties of Cr-SiTa-Al deposition films can meet the specification requirements of 0603 ty...展开更多
ZnO/Cu/ZnO transparent conductive thin films were prepared by RF sputtering deposition of ZnO target and DC sputtering deposition of Cu target on n-type （001） Si and glass substrates at room temperature. The mor- ph...ZnO/Cu/ZnO transparent conductive thin films were prepared by RF sputtering deposition of ZnO target and DC sputtering deposition of Cu target on n-type （001） Si and glass substrates at room temperature. The mor- phology, structure, optical, and electrical properties of the multilayer films were characterized by field emission scanning electron microscope （FESEM）, X-ray diffraction （XRD）, UV/Vis spectrophotometer, and Hall effect mea- surement system. The influence of Cu layer thickness and the oxygen pressure in sputtering atmosphere on the film properties were studied. ZnO/Cu/ZnO transparent conduc- tive film fabricated in pure Ar atmosphere with 10 nm Cu layer thickness has the best performance： resistivity of 2.3 × 10^-4 Ω.cm, carrier concentration of 6.44 × 10^16 cm-2, mobility of 4.51 cm2.（V.s）-1, and acceptable aver- age transmittance of 80 % in the visible range. The trans- mittance and conductivity of the films fabricated with oxygen are lower than those of the films fabricated without oxygen, which indicates that oxygen atmosphere does not improve the optical and electrical properties of ZnO/Cu/ ZnO films.展开更多
Zinc oxide (ZnO) thin films were identified as very suitable piezoelectric material for SAW on the basis of its relatively high electromechanical coupling coefficient,as well as high resistivity for low insertion loss...Zinc oxide (ZnO) thin films were identified as very suitable piezoelectric material for SAW on the basis of its relatively high electromechanical coupling coefficient,as well as high resistivity for low insertion loss and little distortion in the frequency.In this paper ZnO thin films were deposited on Si(100) substrate covered with SiO_2 using a reactive DC magnetic sputtering system from a zinc target.The effects of various deposition parameters on structural and performances have been investigated through experiments.Theoretical and experimental results are also discussed in this paper.XRD showed that the prepared ZnO films had strongly c-axis preferred-orientation.The composition of the film was also determined through high-resolution photoelectron spectroscopy (XPS).AFM showed that the films had smooth surface and that the crystallite sizes of deposited films were in the range 30 nm～50 nm.The above results showed that the films deposited by magnetic sputtering met the demands for surface acoustic wave (SAW) devices.展开更多
Magnetic Fe films grown on single-crystal Mg O(001) and(011) substrates were prepared by direct current magnetron sputtering. The experimental results showed that by applying an external magnetic field of about 300 Oe...Magnetic Fe films grown on single-crystal Mg O(001) and(011) substrates were prepared by direct current magnetron sputtering. The experimental results showed that by applying an external magnetic field of about 300 Oe to film during deposition, a fourfold cubic magnetic anisotropy on Mg O(001) substrate and a twofold uniaxial magnetic anisotropy on Mg O(011) substrate were generated, compared to the isotropic magnetization of Fe film grown without applying the external magnetic field.Our results suggested that external magnetic field during preparation effectively induced relatively higher surface mobility of sputtered Fe atoms and further promoted the crystallization of Fe film and the enhancement of magnetic anisotropy.展开更多
In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field（E-field） tunability of microwave magnetic properties....In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field（E-field） tunability of microwave magnetic properties. With the increase of the E-field from 0 to 8 kV/cm, the magnetic anisotropy field Heffis dramatically enhanced from 169 to 600 Oe, which further leads to a significant enhancement of ferromagnetic resonance frequency from 4.57 to 8.73 GHz under zero bias magnetic field, and a simultaneous decrease of the damping constant α from 0.021 to 0.0186. These features demonstrate that this multiferroic composite is a promising candidate for fabricating E-field tunable microwave components.展开更多
For the purpose of producing high intensity, multiply charged metal ion beams, the dual hollow cathode ion source for metal ions （DUHOCAMIS） was derived from the hot cathode Penning ion source combined with the holl...For the purpose of producing high intensity, multiply charged metal ion beams, the dual hollow cathode ion source for metal ions （DUHOCAMIS） was derived from the hot cathode Penning ion source combined with the hollow cathode sputtering experiments in 2007. To investigate the behavior of this discharge geometry in a stronger magnetic bottle-shaped field, a new test bench for DUHOCAMIS with a high magnetic bottle-shaped field up to 0.6 T has been set up at the Peking University. The experiments with magnetic fields from 0.13 T to 0.52 T have indicated that the discharge behavior is very sensitive to the magnetic flux densities. The slope of discharge curves in a very wide range can be controlled by changing the magnetic field as well as regulated by adjusting the cathode heating power; the production of metallic ions would be much greater than gas ions with the increased magnetic flux density; and the magnetic field has a much higher influence on the DHCD mode than on the PIG mode.展开更多
MnGa films were grown by magnetron sputtering on thermally oxidized Si（Si/SiO2） and glass substrates. Films grown on single-crystal Si（100） substrate with different underlayers were prepared for comparison. It is ...MnGa films were grown by magnetron sputtering on thermally oxidized Si（Si/SiO2） and glass substrates. Films grown on single-crystal Si（100） substrate with different underlayers were prepared for comparison. It is found that the Si/SiO2 substrate is more suitable for growing high-coercivity MnGa films than the glass substrate, which is the result of the isolated-island-like growth. A coercivity of 9.7 kOe can be achieved for the 10 nm MnGa films grown on Si/SiO2 substrate at substrate temperature TS of 450 °C.Optimized experimental conditions are specified by changing the thickness of the MnGa films and the temperature of the substrates.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.10774129 and 60425411)the Ministry of Science and Technology of China
文摘This paper reports that Eu-doped ZnO films were successfully deposited on silicon （100） by radio-frequency magnetic sputtering. The x-ray diffraction patterns indicate that Eu substitutes for Zn in the lattice. Ferromagnetic loops were obtained by using superconducting quantum interference device at 10 K and room temperature. No discontinuous change was found in both of the zero-field-cooled and field-cooled curves. The observed ferromagnetism in Eu-doped ZnO can be attributed to a single magnetic phase. The saturation magnetisation decreased remarkably for the Eu-doped ZnO prepared by introducing 5% of oxygen in the sputtering gas or by the post annealing in O2, suggesting that the defects play key roles in the development of ferromagnetism in Eu-doped ZnO films.
基金supported by Natural Science Foundation of Yunnan Province(2009ZC027M)Innovation Fund of Science and Technology for Students(2012YA027)
文摘La0.9Sr0.1Ga0.8Mg0.2O3–？ （LSGM） electrolyte materials were synthesized by the solid state reaction method. The conductivity of LSGM materials was detected by four probe method, and it was 0.08 S/cm at 850 oC. Dense and uniform films of LSGM materials were deposited by the magnetic sputtering on substrates of Si and La0.7Sr0.3Cr0.5Mn0.5O3–？ （LSCM）. The experimental results showed that the deposition rates dropped and the average grain sizes of the films enlarged with increase in the substrate temperatures. In the sputtering process, the LSGM film was deposited with preferred growth direction. After annealing, the preferred growth direction disappeared and the film surface became smoother and denser. Through observing the deposition process, deposition mechanism was proposed, which was consistent with a model of island growth.
基金Natural Science Foundation of Shanghai Science and Technology Commission (grant No. 11ZR1411300)Pujiang Talent Program of Shanghai Science and Technology Commission (grant No. 11PJ1402700) for the financial support
文摘Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have been formed by a multi-step deposition and natural oxidization of Mg layer. Mg layer thickness,oxygen flow rate and oxidization time were adjusted and the tunnel magnetoresistance(TMR) ratio of optimal MTJs is over 60% at annealing temperature 385. The(001) MgO crystal structure was obtained when the separation distance between MgO target and substrate is less than 6 cm. The TMR ratio of most MgO based MTJs are over 100% at the separation distance of 5 cm and annealing temperature 340. The TMR ratios of MTJs are almost zero when the separation distance ranges from 6 to 10 cm, due to the amorphous nature of the MgO film.
基金Jiangsu Province key laboratory of thin film with Grant No. K2021.
文摘Fe-N films were prepared on Si substrate by dual ion beam sputtering (DIBS). It is found that the crystal structure of the films varies from α-Fe, to ε-Fe2-3N, ε-Fe2-3N +γ-Fe4N, and finally γ'-Fe4N with the increase in substrate temperature (TS). The magnetic properties of the films were investigated by a vibrating sample magnetometer (VSM). The structure of the films is insensitive to the ratios of N2/Ar in main ion source(MIS), and is mainly influenced by the substrate temperature (Ts).
文摘The isothermal and cyclic oxidation behaviors of bulk pure nickel and its magnetically sputtered Ni 0 5Y micro crystal coating were studied at 1?000?℃ in air. Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine structures of the coating and the NiO oxide films. Laser Raman spectrum was also used to measure the stress level in NiO films formed on bulk nickel and the coating. It was found that Ni 0 5Y micro crystal coating had lower oxidation rate, and the grain size of NiO formed on Ni 0 5Y coating was also relatively smaller than that formed on bulk nickel. Meanwhile, the compressive stress level of oxide film formed on Ni 0 5Y coating was lower than that formed on bulk nickel, and the oxide film’s high temperature plasticity was improved in the coating case. The improvements of anti oxidation properties of the sputtered Ni 0 5Y coating were due to the micro crystal structure and the rare earth element Y.
基金Program supported by the National Natural Science Foundation of China(Grant No.51305290)the Higher Education Technical Innovation Project of Shanxi Province,China(Grant No.2013133)+1 种基金the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals of Shanxi Province,China(Grant No.2015003)the Program for the Key Team of Scientific and Technological Innovation of Shanxi Province,China(Grant No.2013131009)
文摘Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si（100） substrates,and subsequently annealed in vacuum at different temperatures for different time.It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films.Interestingly,the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film.The high coercivity of 24.1 kOe（1 Oe = 79.5775 A/m） and remanence ratio（remanent magnetization/saturation magnetization）of 0.94 can be obtained in a Ta/Nd（250 nm）/NdFeB（600 nm）/Nd（250 nm）/Ta film annealed for 3 min at 1023 K.In addition,the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well.The excellent thermal stability can be achieved in a Ta/Nd（250 nm）/NdFeB（600 nm）/Nd（250 nm）/Ta film annealed at1023 K.
基金Supported by Science and Technology Committee of Tianjin (No.06YFGPGX08400)Ministry of Science and Technology of China (No.2009GJF20022)Innovation Fund of Tianjin University
文摘High resistance thin film chip resistors(0603 type) were studied,and the specifications are as follows:1 k? with tolerance about ±0.1% after laser trimming and temperature coefficient of resistance(TCR) less than ±15×10-6/℃.Cr-Si-Ta-Al films were prepared with Ar flow rate and sputtering power fixed at 20 standard-state cubic centimeter per minute(sccm) and 100 W,respectively.The experiment shows that the electrical properties of Cr-SiTa-Al deposition films can meet the specification requirements of 0603 ty...
基金financially supported by the National Nature Science Foundation of China (No. 21071098)the Project of International Cooperation of the Ministry of Science and Technology of China (No. 2011DFA50530)the Nanotechnology Program of Shanghai Science & Technology Committee (No. 12nm0504800)
文摘ZnO/Cu/ZnO transparent conductive thin films were prepared by RF sputtering deposition of ZnO target and DC sputtering deposition of Cu target on n-type （001） Si and glass substrates at room temperature. The mor- phology, structure, optical, and electrical properties of the multilayer films were characterized by field emission scanning electron microscope （FESEM）, X-ray diffraction （XRD）, UV/Vis spectrophotometer, and Hall effect mea- surement system. The influence of Cu layer thickness and the oxygen pressure in sputtering atmosphere on the film properties were studied. ZnO/Cu/ZnO transparent conduc- tive film fabricated in pure Ar atmosphere with 10 nm Cu layer thickness has the best performance： resistivity of 2.3 × 10^-4 Ω.cm, carrier concentration of 6.44 × 10^16 cm-2, mobility of 4.51 cm2.（V.s）-1, and acceptable aver- age transmittance of 80 % in the visible range. The trans- mittance and conductivity of the films fabricated with oxygen are lower than those of the films fabricated without oxygen, which indicates that oxygen atmosphere does not improve the optical and electrical properties of ZnO/Cu/ ZnO films.
文摘Zinc oxide (ZnO) thin films were identified as very suitable piezoelectric material for SAW on the basis of its relatively high electromechanical coupling coefficient,as well as high resistivity for low insertion loss and little distortion in the frequency.In this paper ZnO thin films were deposited on Si(100) substrate covered with SiO_2 using a reactive DC magnetic sputtering system from a zinc target.The effects of various deposition parameters on structural and performances have been investigated through experiments.Theoretical and experimental results are also discussed in this paper.XRD showed that the prepared ZnO films had strongly c-axis preferred-orientation.The composition of the film was also determined through high-resolution photoelectron spectroscopy (XPS).AFM showed that the films had smooth surface and that the crystallite sizes of deposited films were in the range 30 nm～50 nm.The above results showed that the films deposited by magnetic sputtering met the demands for surface acoustic wave (SAW) devices.
基金supported by the National Natural Science Foundation of China(51332001 and 51402164)Tsinghua University Initiative Scientific Research Program(2014Z21010 and 2014Z01006)
文摘Magnetic Fe films grown on single-crystal Mg O(001) and(011) substrates were prepared by direct current magnetron sputtering. The experimental results showed that by applying an external magnetic field of about 300 Oe to film during deposition, a fourfold cubic magnetic anisotropy on Mg O(001) substrate and a twofold uniaxial magnetic anisotropy on Mg O(011) substrate were generated, compared to the isotropic magnetization of Fe film grown without applying the external magnetic field.Our results suggested that external magnetic field during preparation effectively induced relatively higher surface mobility of sputtered Fe atoms and further promoted the crystallization of Fe film and the enhancement of magnetic anisotropy.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674187)
文摘In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field（E-field） tunability of microwave magnetic properties. With the increase of the E-field from 0 to 8 kV/cm, the magnetic anisotropy field Heffis dramatically enhanced from 169 to 600 Oe, which further leads to a significant enhancement of ferromagnetic resonance frequency from 4.57 to 8.73 GHz under zero bias magnetic field, and a simultaneous decrease of the damping constant α from 0.021 to 0.0186. These features demonstrate that this multiferroic composite is a promising candidate for fabricating E-field tunable microwave components.
基金Supported by National Natural Science Foundation of China(11105008,10775011)
文摘For the purpose of producing high intensity, multiply charged metal ion beams, the dual hollow cathode ion source for metal ions （DUHOCAMIS） was derived from the hot cathode Penning ion source combined with the hollow cathode sputtering experiments in 2007. To investigate the behavior of this discharge geometry in a stronger magnetic bottle-shaped field, a new test bench for DUHOCAMIS with a high magnetic bottle-shaped field up to 0.6 T has been set up at the Peking University. The experiments with magnetic fields from 0.13 T to 0.52 T have indicated that the discharge behavior is very sensitive to the magnetic flux densities. The slope of discharge curves in a very wide range can be controlled by changing the magnetic field as well as regulated by adjusting the cathode heating power; the production of metallic ions would be much greater than gas ions with the increased magnetic flux density; and the magnetic field has a much higher influence on the DHCD mode than on the PIG mode.
基金financially supported by the National Natural Science Foundation of China (Nos. 51590883, 51471167, 51271179 and 51571194)the project of Chinese Academy of Sciences with grant number KJZD-EW-M05-3supported by a Joint Research Project from Ministry of Science, ICT and Future Planning/Korea Research Council for Industrial Science and Technology
文摘MnGa films were grown by magnetron sputtering on thermally oxidized Si（Si/SiO2） and glass substrates. Films grown on single-crystal Si（100） substrate with different underlayers were prepared for comparison. It is found that the Si/SiO2 substrate is more suitable for growing high-coercivity MnGa films than the glass substrate, which is the result of the isolated-island-like growth. A coercivity of 9.7 kOe can be achieved for the 10 nm MnGa films grown on Si/SiO2 substrate at substrate temperature TS of 450 °C.Optimized experimental conditions are specified by changing the thickness of the MnGa films and the temperature of the substrates.
