Effect of Ti cap layer thickness on microstructures and magnetic properties of Ti/Ni/Ti films

Nanogranular Ti (3 nm)/Ni(30 nm)/Ti(t nm) (t=1, 3, 5, 7, 10) films were prepared by facing magnetron sputtering from Ti and Ni onto glass substrates at room temperature. The structural and magnetic properties of films strongly depended on the Ti layer thickness. X-ray diffraction (XRD) patterns of all as-deposited films showed strong FCC Ni(111) peak. Vibrating sample magnetometer (VSM) measurements indicated that the perpendicular coercivity of the Ti (3 nm)/Ni (30 nm)/Ti (3 nm) film reached about 36 kA/m. With the increase of Co layer thickness, coercivity (H_c) first increased and then decreased. The grain size and magnetic clusters slightly increased and the value of roughness (R_a) was smallest at t=3 nm.     

SmCo/Co多层交换弹性纳米晶复合永磁薄膜的制备和磁耦合研究

利用磁控溅射的方法,在室温条件的Si基片上制备了[SmCo(25nm)/Co(x)]4/SmCo(25 nm)多层交换弹性纳米晶复合永磁薄膜(Co层厚度x=0～10 nm),经过550 ℃/20 min的真空退火处理使薄膜结晶后,进行磁性测试和磁耦合分析.结果表明:SmCo层厚度固定为25 nm时,调整Co层的厚度,从0至10 nm逐渐增加,矫顽力从2270.3 kA·m-1逐渐降低至1040.5 kA·m-1,同时,饱和磁化强度和剩磁随Co层厚度增加逐渐增加,上升了60％.当加入10 nm的Co层后,多层膜的最大磁能积比125 nm的单层SmCo薄膜增加了46％.另外,与SmCo/Co双层交换弹性薄膜在退磁过程中表现的零场附近的软硬磁双相行为相比,SmCo/Co多层交换弹性薄膜表现出单相反转行为,说明体系中的两种磁性层具有更好的磁耦合.经过磁耦合研究发现,当Co软磁层较薄时,薄膜中磁性颗粒以颗粒间交换耦合为主;当软磁层厚度增加时,颗粒间交换耦合减弱,静磁耦合增强,保证了软硬磁相之间的良好磁耦合作用.Co层的加入有效地提高了薄膜的磁性能.     

Effect of film thickness on magnetic properties of Cr/SmCo/Cr films

Cr/SmCo/Cr films with different SmCo thickness were deposited on glass substrates by magnetron sputtering,followed by an annealing process at 550 °C for 20 min.Experimental results showed that the SmCo film of 30 nm exhibited two-phase behavior in the demagnetization process,the obvious kink was observed near zero.For the SmCo film of 50 nm,the kink was invisible,and a single phase like behavior was obtained in the demagnetization process.The reversal behavior became consistent in the thicker films.Moreover,the coercivity reduced and the saturated magnetization increased obviously with the increasing thickness.X-ray diffraction results indicated that the average grain size of SmCo 5 in the thicker films were almost 30 nm,but the quantity of SmCo 5 grains increased with the increasing thickness,which enhanced the intergrain exchange coupling(IEC) of the SmCo 5 hard phases.The increase of IEC improved the magnetic properties of SmCo films with increasing thickness.     

利用钛过渡层及掺钼改善声表面波器件用铝薄膜的微结构与性能

纯铝薄膜以其低声阻抗特性被广泛应用于声表面波（SAW）器件的制作。随着通讯频率的不断提高，对SAW器件用Al薄膜的功率承受力以及与基体的附着力提出了越来越高的要求。采用少量易于反应离子刻蚀的Mo元素掺杂来改善Al合金的抗电迁移和功率承受力，并以数纳米的Ti过渡层增强Ao-Mo合金薄膜的取向性。结果表明：Ti／Al-Mo薄膜表现出强（111）织构，与纯Al薄膜相比，晶粒明显细化且致密均匀，临界载荷大大增加，与基体的附着力显著增强，并具有良好的刻蚀性能。     

Magnetic Coupling in La0.67 Ca0.33 MnO3／La0.67 Sr0.33 CoO3／La0.67 Ca0.33MnO3 Trilayer Films

The perovskite La0.67 Ca0.33 MnO3/La0.67 Sr0.33 CoO3/La0.67 Ca0.33 MnO3 trilayers were fabricated by a facing-target sputtering technique and their magnetotransport properties were investigated. The magnetoresistance is dependent on spacer thickness and dramatically decreases when La0.67 Sr0.33 CoO3 layer is thick enough because of its short-circuiting effect. Different from La0.67 Ca0.33 MnO3 single layer, trilayer films with thin La0.67 Sr0.33 CoO3 spacer have the enhanced metal-semiconductor transition temperature (TMS) of La0.67 Ca0.33 MnO3 layers. The magnetic coercivity Hc shows a nonmonotonic behavior with changing the spacer layer thickness at 230 K. The waist-like hysteresis indicates that there is an indirect exchange coupling between the top and bottom Lao.67 Ca0.33 MnO3 layers across the spacer La0.67 Sr0.33 CoO3 layer.     

Crystal structure,microstructure and magnetic properties of SmCo-based films treated by different annealing methods

Effect of conventional thermal annealing(CTA) and rapid recurrent thermal annealing(RRTA) processes on crystal structure,mi-crostructure,and magnetic properties of the SmCo-based films were investigated.The results indicated that the CTA-treated films exhibited poor permanent magnetic properties,and a low intrinsic coercivity of 72.8 kA/m was observed.Wide hysteresis loop was obtained for the RRTA-treated films,providing better permanent magnetic properties.The intrinsic coercivity reached 312.0 kA/m.According to the X-ray diffraction(XRD) and atomic force microscopy(AFM) results,the magnetic properties of the CTA-treated films and RRTA-treated films were found to be correlated with the crystal structure and microstructure,which were strongly determined by the annealing treatment.CTA treatment led to poor crystallization effects for the films,and a rough surface(RMS=3.47 nm and P-V=35.42 nm) and large grain size of 92.7 nm were observed correspondingly.However,the RRTA treatment exhibited great contributions on the crystallization of the films,which is accountable for the smooth surface(RMS=2.047 nm and P-V=16.43 nm) and fine grain size of 60.8 nm.     

Magnetic and magnetostrictive properties of amorphous TbFe/FeAl multilayer thin film

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/FeAl multilayer thin film compared with TbFe single layer film were obviously improved. In comparison with the intrinsic coercivity JHc 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/FeAl multilayer thin film.     

Tensile strength of Ni/Cu/(001)Ni triple layer films

Tensile properties of Ni/Cu/(001)Ni triple layer films and single crystal films of (00l)Cu and (00l)Ni were studied. The specimen films having the thickness of 50 to 500 nm were prepared by the epitaxial evaporations on (001)NaCl substrates. The stress-strain curves of tensile tests in the direction of [100] of Ni/Cu/(001)Ni triple layer films were almost linear until fracture and showed extremely small plastic deformation. The yield stresses of these specimens were 600 to 700 MPa independently of the layer thicknesses, which were 2.5 to 5 times higher than those of Ni or Cu single crystal films, and were also higher than the values given by the mixture rule for Ni and Cu single crystal films. The increase of yield stress was evaluated from the repulsive force acting on the mobile dislocations originating from the stress fields of misfit dislocation arrays at the Ni-Cu interface. Formerly Graduate Student, Faculty of Engineering, Osaka University     

射频磁控溅射法制备Ti掺杂ITO薄膜的厚度对膜结构与光电性能的影响

利用Ti掺杂ITO靶材,采用单靶磁控溅射法在玻璃基底上制备厚度为50~300 nm的ITO:Ti薄膜。借助X射线衍射(XRD)、原子力显微镜(AFM)、可见光分光光度计、霍尔测试系统和四探针电阻测量仪,研究薄膜厚度对薄膜的晶体结构、表面形貌和光电性能的影响。结果表明:ITO:Ti薄膜呈现(400)择优取向,随薄膜厚度增加,薄膜的结晶程度增强,晶粒度增大,薄膜更致密。随薄膜厚度增加,薄膜的均方根粗糙度和平均粗糙度以及电阻率都先减小再增加,薄膜厚度为250 nm时,表面粗糙度最小,蒋膜厚度为200 nm时,电阻率最低,为2.1×10-3?·cm。不同厚度的薄膜对可见光区的平均透过率都在89%以上。     

Effect of chromium interlayer on magnetic exchange coupling of SmCo/Cr/TbFeCo multilayer thin films

A series of SmCo/Cr/TbFeCo multilayer thin films with perpendicular anisotropy were prepared by RF- magnetron sputtering system, and the effects of Cr interlayer thickness on magnetic properties and interlayer exchange coupling were investigated. It was found that the magnetic properties varied with the thickness of Cr interlayer, especially the values of saturation magnetization Ms and the coercivity Hc fluctuated periodically with the thickness of Cr interlayer. STM images revealed that the variation of coercivity Hc was attributed to the microstructure change of SmCo layer influenced by Cr interlayer, and the variation of Ms was related to interlayer exchange coupling.     

Ti(C,N)含量和烧结温度对梯度硬质合金脱β层厚度的影响

以Ti(C,N)为N源,在脱氮气氛下烧结制备WC-TiC-Ti(C,N)-TaC-NbC-Co硬质合金,研究Ti(C,N)含量和烧结温度对脱β层厚度及合金微观组织与性能的影响。结果表明:随Ti(C,N)的质量分数从0.5%增加到1.5%,脱β层厚度持续增大。随烧结温度升高,脱β层厚度增大,增大的幅度随Ti(C,N)含量增加而增大。合金的密度、硬度和矫顽磁力不受Ti(C,N)含量的影响,但随烧结温度升高,合金的硬度降低、矫顽磁力变小、WC平均晶粒尺寸增大且直边化。脱β层中无明显的WC晶粒异常长大现象,脱β层厚度由Ti的扩散和N含量决定。     

磁控溅射Ti/WO_3薄膜的微结构及光学性能

采用直流反应磁控溅射技术在玻璃基片上制备不同氧分压的Ti掺杂的WO3薄膜。用X射线衍射(XRD)、分光光度计、台阶仪等对薄膜的结构、光学性质进行表征;分析不同的氧分压对气敏薄膜透光率和结构的影响。结果表明,氧分压增大,膜厚减小,薄膜的平均晶粒尺寸增大,晶面间距增大,光学带隙变小。并用包络线法和经验公式法计算出薄膜的光学常数,结果表明,折射率和消光系数随氧分压的增加而增大。     

Thermodynamic activities and phase boundaries for the alloys of the Ni3Al-Ni3Ti pseudobinary section in the Ni-Al-Ti system

The pseudobinary section Ni₃Al-Ni₃Ti of the ternary Ni-Al-Ti system has been investigated by ther-mal analysis and Knudsen effusion mass spectrometry. The solidus of the pseudobinary section and the thermodynamic activities of Ni and Al have been determined in the alloys Ni_0.75A1_0.25-xTi_x of the compositionsx = 0.00 to 0.21. Moreover, the thermodynamic activities of Ni and Ti in Ni₃Ti (x = 0.25) as well as the Gibbs energy of mixing of the Ni_0.75Ti_0.25 phase resulted. The ionization cross-sectional ratio Σ(Ni)/Σ(Ti) = 0.77 has been evaluated for the electron impact energy of 50 eV.     

Laser Melting Deposition of CP-Ti/Ti–0.4Ni Graded Material for Structural Applications

Metallurgical and Materials Transactions A - In this study, microstructural evolution and strengthening of commercial purity Ti (CP-Ti)/Ti–0.4Ni graded material (GM) fabricated by laser...     

渣成分对高温合金0Cr15Ni25Ti2MoAlVB 电渣重熔Ti烧损率和钢锭表面质量的影响

试验分析了2.5 t电渣炉使用4种成分熔渣重熔0Cr15Ni25Ti2MoAlVB合金时的Ti烧损率。试验结果表明,4种渣系中75%CaF₂-15%Al₂O₃-10%CaO三元提纯渣的Ti烧损率最低,为7.0%,并且避免了70%CaF₂-30%Al₂O₃的二元渣系重熔钢锭表面渣沟等缺陷。     

TbCo／Cr Amorphous Film with Perpendicular Magneto-Anisotropy

Amorphousrareearth transitionmetalalloy (RE TM)films[1] havebeenintensivelystudied .Sincetheamorphousfilmsoftenpossessaverylargeuniaxialanisotropywithitseasyaxisperpendiculartothefilmplane ,theycanbeusedasmagneto optical[2 ] orhy bridrecordingmedia[3] .Amongthosefilms ,Tb Cofilmsareofgreatinterestbecauseoftheirhighcoer civeforce ,largeperpendicularanisotropyandeasycontroloftheirsaturationmagnetizationthroughcom positionadjustment[4 ] .However ,theTb Cofilmshavesuchadisadvantagethatsubstrate…     

双层复合永磁薄膜磁性能的模拟研究

利用微磁学理论模拟计算了Nd2Fe14B／α-Fe双层复合永磁薄膜的磁滞回线,并对双层膜体系的剩磁、矫顽力与软磁层厚度的关系进行了研究。结果显示,软磁层厚度小于临近尺寸时,磁滞回线为矩形,双层膜完全耦合;软磁层厚度与磁性能的关系表明,随着软磁层厚度的增加,剩磁先增大后减小,而矫顽力单调下降。     

氩气流量、渣系和加Al粉对1Cr21Ni5Ti钢保护气氛重熔锭[Ti]的影响

生产试验了氩气流量（15~45 L/min）,三元（/%:63CaF₂,27Al₂O₃,10CaO）、四元（/%:53CaF₂,22Al₂O₃,20CaO,5MgO）和五元（/%:50CaF₂,22Al₂O₃,20CaO,5MgO,3TiO₂）渣系和重熔过程加Al粉对3 t保护气氛重熔1Cr21Ni5Ti钢锭[/%:0.09~0.14C,≤0.80Mn,≤0.80Si,≤0.025S,≤0.035P,4.8~5.8Ni,20~22Cr,5×（C-0.02~ 0.65Ti]中[Ti]的影响。结果表明,增加氩气流量,采用五元渣系和重熔过程均匀加入Al粉可使重熔锭平均钛的烧损△[Ti]≤0.15%。采用优化工艺在6 t保护气氛电渣炉,填充比0.58,电流12 500~13 500 A,电压40~43 V,,氩气流量30 L/min,重熔1Cr21Ni5Ti钢的结果表明,电渣锭成分稳定,C含量0.090%~0.091%;Ti含量0.46%~0.52%。      

Nanocrystallization and magnetic properties of Fe-30 weight percent Ni alloy by surface mechanical attrition treatment

A nanostructured surface layer was formed in Fe-30 wt pct Ni alloy by surface mechanical attrition treatment (SMAT). The microstructure of the surface layer after SMAT was investigated using optical microscopy, X-ray diffraction, and transmission electron microscopy. The analysis shows that the nanocrystallization process at the surface layer starts from dislocation tangles, dislocation cells, and subgrains to highly misoriented grains in both original austenite and martensite phases induced by strain from SMAT. The magnetic properties were measured for SMAT Fe-30 wt pct Ni alloy. The saturation magnetization (M _s ) and coercivity (H _c ) of the nanostructured surface layers increase significantly compared to the coarse grains sample prior to SMAT. The increase of M _s for SMAT Fe-30 wt pct Ni alloy was attributed to the change of lattice structure resulting from strain-induced martensitic transformation. Meanwhile, H _c was further increased from residual microstress and superfined grains. These were verified by experiments on SMAT pure Ni and Co metal as well as liquid nitrogen-quenched Fe-30 wt pct Ni alloy.     

Model for Calculating J(H) Curves of Ni Coated Nd-Fe-B Magnets

An analytical model to describe the influence of surface degradation and the Ni layer itself on the magnetic properties of Ni coated Nd-Fe-B magnets is presented. Starting from the bulk magnetic properties, the dimensions, the thickness of Ni coating and the affected surface layer, J(H) demagnetization curve is calculated. Subsequently the expected values of (BH)_max, and the reversible permeability are deduced from the calculated J(H) curves. For flat magnets the surface effects lead to a decrease of B_r and an increase of the permeability which lowers (BH)_max. For strait magnets a step in the J(H) curve appears at H = 0. The deteriorating effect of Ni coating and the surface layer scale with the dimensions of magnet and the thickness of these layers, which depend on the processing and the grain size of magnet. These effects can not be neglected if one or more dimensions of a Ni coated magnet are less than about 5 mm. SmCo₅ magnets show similar effects but the coercivity of the damaged surface layer is higher. Pinning type Sm₂Co₁₇ magnets show almost no deterioration on surface due to machining. As a result, Sm-Co magnets are better suited for applications with dimensions smaller than about 2 mm.