Co_（22）Ag_（78）颗粒膜巨磁电阻及微结构

本文报道了在室温条件下采用离子束共溅射技术制备的Ｃｏ２２Ａｇ７８颗粒膜的巨磁阻（ＧＭＲ）效应及其微结构。ＧＭＲ采用直流四探针法测量，给出了ＧＭＲ与外场和退火温度的关系．透射电子显微镜、电子衍射和Ｘ射线衍射结果显示样品呈现面心立方（ｆｃｃ）结构，并具有（１１１）织构。利用透射电子显微镜配备的摄象系统对样品中Ｃｏ颗粒在退火条件下的形变和生长进行了实时观测。铁磁共振结果表明，在退火过程中Ｃｏ颗粒形变和生长主要沿膜面进行。     

Co—Ag颗粒膜撩光克尔效应

用直流离子束共溅射技术溅射Ｃｏ－Ｃｇ复合靶,制备了一系列Ｃｏ含量不同的颗粒膜,薄膜厚度约为４００ｎｍ,含Ｃｏ的体积比从０．０３到０．８４。在室温下,测量了Ｃｏ－Ａｇ颗粒膜的极克尔角θｋ的磁光谱,测量的波长范围从４００ｎｍ到８５０ｎｍ。     

界面散射对Ni_(80)Co_(20)/M(M=Co,Cr,Ag)多层膜各向异性磁电阻的影响

用磁控溅射方法制备了Ｎｉ８０Ｃｏ２０／Ｍ（Ｍ＝Ｃｏ,Ｃｒ,Ａｇ）多层膜样品系列,Ｃｏ,Ｃｒ,Ａｇ杂质层的标称厚度为０．１ｎｍ,研究了界面散射对多层膜的磁及输运性质的影响．零场电阻率ρ的测量结果表明,对含Ｃｒ样品,ρ随杂质层间距Ｌ的依赖关系能较好的用Ｆｕｃｈｓ－Ｓｏｎｄｈｅｉｍｅｒ（Ｆ－Ｓ）理论描述．而对含Ｃｏ和Ａｇ样品,ρ随Ｌ的依赖关系在Ｌ小于１５ｎｍ时开始偏离Ｆ－Ｓ理论．磁电阻测量表明,含Ｃｒ和Ａｇ样品,各向异性磁电阻Δρ在Ｌ＜１５ｎｍ时随Ｌ的减小陡然下降．对含磁性Ｃｏ元素的样品,其Δρ值在Ｌ＞１５ｎｍ时高于Ｎｉ８０Ｃｏ２０单层薄膜的Δρ值;在Ｌ＜１５ｎｍ时Δρ值随Ｌ呈现振荡变化的趋势．磁性测量表明,三个系列样品的矫顽力Ｈｃ在Ｌ＜１５ｎｍ时都随Ｌ近似直线上升,在Ｌ＞１５ｎｍ后趋于饱和;经４００℃真空退火后Ｈｃ都显著下降．     

Co-Ag颗粒膜的磁光克尔效应

用直流离子束共溅射技术溅射Ｃｏ－Ａｇ复合靶，制备了一系列Ｃｏ含量不同的颗粒膜，薄膜厚度约为４００ｎｍ，含Ｃｏ的体积比从０．０３到０．８４。在室温下，测量了Ｃｏ－Ａｇ颗粒膜的极克尔角θｋ的磁光谱，测量的波长范围从４００ｍｍ到８５０ｍｍ。当外磁场大小为１．０Ｔ并且方向垂直于膜面时，得到的最大克尔角为０．２８°，结果显示在颗粒膜极克尔旋转中，钴颗粒的浓试和微结构起重要作用。     

退火[Co＼Cu]多层膜的固相反应与磁性

用双对向靶溅射方法制备了两种成分的「Ｃｏ（１．２ｎｍ）／Ｃｕ（ｔＣｕ）」（ｔＣｕ＝１．０ｎｍ，３．４ｎｍ）纳米多层膜。分别用ＴＥＭ和ＴＧ方法研究了「Ｃｏ／Ｃｕ」多层膜结构和磁怀随温度的变化。结果表明：ｔＣｕ＝１．０ｎｍ的多层样品出现了两个磁性转变点，这是因为样品中存在的两种磁性物质。ＴＥＭ分析结果证明这两种铁磁相为ｈｃｐＣｏ－Ｃｕ固溶体。     

磁控反应溅射制备GexC1—x薄膜的结构

利用射频磁控反应溅射以Ａｒ、ＣＨ４为原料气体,在较宽的工艺参数范围内制备出了ＧｅｘＣ１－ｘ薄膜。利用Ｘ射线衍射（ＸＲＤ）、Ｘ射线光电子谱（ＸＰＳ）对制备的薄膜进行了分析。结果表明,ＧｅｘＣ１－ｘ薄的结构强烈领事于制备的工艺参数。当沉积温度较低、射频功率不大时,ＧｅｘＣ１－ｘ薄膜主要为非晶态结构。随着沉积温度升高、射频功率增大,薄膜中出现Ｇｅ微晶相。ＧｅｘＣ１－ｘ薄膜中Ｇｅ与Ｃ发生电荷的转移,形成化     

Growth of Ga_xIn_（1－x）Sb Alloys by MOCVD—Solid Composition Surface Morphology and Electrical Propert

ＧｒｏｗｔｈＯｆＧａ＿ｘＩｎ＿（１－ｘ）ＳｂＡｌｌｏｙｓｂｙＭＯＣＶＤ—ＳｏｌｉｄＣｏｍｐｏｓｉｔｉｏｎＳｕｒｆａｃｅＭｏｒｐｈｏｌｏｇｙａｎｄＥｌｅｃｔｒｉｃａｌＰｒｏｐｅｒｔｉｅｓＺｈａｎｇＢａｏｆｉｎ，ＺｈｏｕＴｉａｎｍｉｎｇ，ＪｉａｎｇＨｏｎ...     

贵金属光学金相图谱之八

图①Ｐｄ－Ａｇ－Ｇｄ合金（３２×）浸蚀剂（ＨＣｌ＋ＣｒＯ３）,铸态组织,具有明显的树枝晶偏析。Ｅｔｃｈａｎｔ（ＨＣｌ＋ＣｒＯ３）,ｃａｓｔｓｔａｔｅ,ｂｒａｎｃｈｃｒｙｓｔａｌｓｅｇｒｅｇａｔｉｏｎｏｂｖｉｏｕｓ．图②Ａｕ－ＲＥ合金（６００×）浸蚀剂...     

Ag—Cu纳米合金的微观结构

利用高分辨电镜（ＨＲＥＭ）对气相凝聚法制备的Ａｇ１－ｘＣｕｘ（０．０５≤ｘ≤０．４０）纳米合金样品中的微观结构进行了研究．结果表明，在所有合金样品中，都没有观察到明显的界面亚稳相的形成，且晶界具有有序的原子结构样品中两组元的等轴纳米晶粒分布均匀，但随着Ｃｕ含量的增加，Ｃｕ颗粒出现明显的偏聚和粗化；与稳定相相比，富Ａｇ和富Ｃｕ相的点阵常数没有发生显著的变化．     

EQUILIBRIUM PHASE DIAGRAMS IN SYSTEM CuO-PbO-Ag

ＥＱＵＩＬＩＢＲＩＵＭＰＨＡＳＥＤＩＡＧＲＡＭＳＩＮＳＹＳＴＥＭＣｕＯ－ＰｂＯ－Ａｇ￥ＳＨＡＯＺｈｏｎｇｂａｏ;ＬＩＵＫｕｉｒｅｎ;ＭＥＮＧＢｏ;ＬＩＹｉｎｇ;ＹＡＮＧＹｕｑｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ,Ｎｏｒｔｈｅａｓｔｅｒｎ...     

Effect of Ti layer thickness on microstructure and magnetic properties of Ti/Co/Ti films

TiCoTi granular films were prepared by DC facing-target magnetron sputtering system onto glass substrates and subsequently in situ annealing in vacuum. Structural of Ti ( t nm)/Co (40 nm)/Ti ( t nm) films were investigated in detail, which shows that the majority Co nanograins are formed as the hexagonal-close-packed (HCP) structure. Vibrating sample magnetometer (VSM) and scanning probe microscope (SPM) were applied to study the magnetic properties, morphologies and domain structures of these samples. It has been found that the structure and magnetic properties of the Ti/Co/Ti films depend strongly on the Ti layer thickness. The out-of-plane coercivities ( Hc) of the film is maximum about 78.8 kA·m-1 when t =5 nm with annealing at 300 ℃; the distributing of grains of the sample is uniformity; and the average size of particles is about 13 nm. The obtained results suggest that this system is perpendicular anisotropy and might be applicable to perpendicular magnetic recording media.     

Substrate temperature dependence of chemical state and magnetoresistance characteristics of Co–TiO2 nanocomposite films

Co−TiO₂ nanocomposite films were prepared via magnetron sputtering at various substrate temperatures. The films comprise Co particles dispersed in an amorphous TiO₂ matrix and exhibit coexisting ferromagnetic and superparamagnetic properties. When the substrate temperature increases from room temperature to 400 °C, Co particles gradually grow, and the degree of Co oxidation significantly decreases. Consequently, the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400 °C. At a high substrate temperature, conductive pathways form among some of the clustered Co particles. Thus, resistivity rapidly declines from 1600 to 76 μΩ·m. The magnetoresistive characteristic of Co−TiO₂ films is achieved even at resistivity of as low as 76 μΩ·m. These results reveal that the obtained nanocomposite films have low Co oxidation, high magnetization and magnetoresistance at room temperature.     

淀粉包覆纳米银粒子的简易合成及其抗菌性能

采用直流磁控溅射技术,在n-Si (100)衬底上制备了CoxC100-x(x=2.5～50,at％)颗粒膜,并对薄膜的结构、形貌、磁性能和巨磁电阻(GMR)效应做了系统的研究.结果表明:制备态的Co-C薄膜为非晶结构,且表面光滑、颗粒尺寸及膜厚度均匀;随热处理温度的增加,Co成分在300℃逐渐开始晶化,400℃基本晶化完全,500℃度的时候膜层开始出现裂纹;拉曼光谱显示制备态薄膜为类金刚石(DLC)薄膜;X射线光电子能谱(XPS)分析表明,包埋在碳基薄膜中的Co掺杂纳米颗粒以单质形态存在,没有Co的碳化物出现,且Co掺杂没有促进碳膜的石墨化,Co-C纳米复合薄膜组成了一个互不相溶的金属/绝缘体体系;磁性能测试显示薄膜的饱和磁化强度(Ms)和矫顽力(Hc)与Co的含量和颗粒的晶化程度有密切关系;磁电阻测量结果表明Co2.5C97.5薄膜具有高达36％的正GMR效应,GMR效应遵循输运通道的转变机制.     

Co含量对Co-C纳米复合薄膜磁性能和磁电阻的影响

采用磁控共溅射法制备了Co含量介于6.4at%~16.4at%的Co-C纳米复合薄膜。形貌观察表明,Co纳米颗粒均匀分散在C基体中,相邻Co颗粒被C基体较好地分离,样品呈现典型的颗粒薄膜结构。Co颗粒平均尺寸随Co含量增加而增大。薄膜在低温下磁性较强,在室温下磁性较弱;磁化强度随Co含量增加显著提高。当温度为4.2K、磁场为90×79.6kA·m-1时,在Co含量为6.4at%、8.3at%和9.6at%的Co-C薄膜中分别观察到9.1%、4.3%和1.9%的负磁电阻,为碳基磁性颗粒薄膜获得优异磁输运性能提供可能。受微结构变化影响,样品磁电阻值随Co含量的增加而下降。     

Preparation of Gd-Co alloy film in acetamide-urea-NaBr melt

Electroreduction of Co(Ⅱ） to metallic Co in acetamide-urea-NaBr metl at 353K is irreversible in one step.Gd(Ⅲ） is not reduced to Gd alone,but can be inductively codeposited with Co(Ⅱ.The amorphous Gd-Co alloy films were obtained by potentiostatic electrolysis.With the cathode potential shifting to negative direction.the content of gadolinium in the alloy increases and can get to 65.89%(mass fraction).The additive of Na2EDTA can make the diameter of the particles of crystalline alloy smaller and change the shape of particles.     

Carbon films containing transition metal particles of nano and submicron sizes

Aromatic polyimide films containing cobalt compounds were prepared by mixing Co(NO₃)₂ and CoCl₂ with a polyamic acid in solution and following imidization on glass plates. The effect of heat treatment on structure, texture and magnetic property of the films was investigated, and the formation process of ferromagnetic particles of nano and submicron sizes in the films was examined. As the particle sizes increased with increasing heat treatment temperature (HTT), the magnetic property changed from superparamagnetic to ferromagnetic, and the ferromagnetic particles of single magnetic domain transferred to those with multi-magnetic domain by further heat treatment. The distribution of metal particle size became very wide by the heat treatment. Pores were found on the surfaces of the heat-treated films, and pore sizes were very similar to those for the metal particles, suggesting that pores were paths of the particle movements. These results were compared with those obtained previously for the polyimide films containing nickel and iron compounds. Different metal compounds introduced in polyimide films gave different processes of the formation and growth of metal particles and pores as HTT increased.     

CoCu合金颗粒膜的室温磁电阻效应

利用射频磁控溅射方法制备ＣｏＣｕ合金不同成分的亚稳态薄膜。研究了ＣｏＣｕ合金颗粒膜的磁电阻随真空退火温度、外磁场以及组元成分而变化的规律。经真空退火后，ＣｏＣｕ颗粒膜中析出的Ｃｏ颗粒呈面心立方结构。这种在非磁性Ｃｕ的基体上和具有磁性Ｃｏ偏聚态的纳米级颗粒膜具有巨磁阻（ＧＭＲ）效应。ＣｏＣｕ颗粒膜的ＧＭＲ效应及磁性能均取决于Ｃｏ颗粒的尺寸及数量。     

Microstructure and magnetic properties of electrodeposited Gd-Co alloy films

Gd-Co alloy films were synthesized by potentiostatic electrolysis on Cu substrates in urea-acetamide-NaBr-KBr melt at 353 K. The elec- troreduction of Co2 and Gd3 was investigated by cyclic voltammetry. The reduction of Co2 is an irreversible process. Gd3 cannot be re- duced alone, but it can be inductively co-deposited with Co2 . Both the Gd content and microstructure of the prepared Gd-Co alloy films can be controlled by the deposited potential. The content of Gd was analyzed using an inductively coupled plasma emission spectrometer (ICPES), and the microstructure was observed by scanning electron micrograph (SEM). The films were crystallized by heat-treatment at 823 K for 30 s in Ar atmosphere, and then were investigated by XRD. The hysteresis loops of the Gd-Co alloy films were measured by a vibrat- ing sample magnetometer (VSM). The experimental results reveal that the deposited Gd-Co alloy films are amorphous, while the annealing causes the samples to change from amorphous to polycrystalline, thus enhancing their magnetocrystalline anisotropy and coercivity. More- over, the magnetic properties of the Gd-Co alloy films depend strongly on the Gd content.     

磁控溅射Co/AZO纳米复合薄膜的结构及光学性能

利用对靶磁控溅射交替沉积技术在不同Co靶电流下沉积Co/AZO纳米复合薄膜,并对其进行真空退火。研究了Co靶电流对薄膜的结构及光学性能的影响。结果表明,沉积态薄膜晶化程度随Co靶电流增加而降低,未发现Co的相关衍射峰;真空退火后,薄膜结晶性明显改善,0.3 A薄膜中出现了Co纳米颗粒,当Co靶电流增大到0.5 A时还发现了CoO纳米颗粒。UV-Vis光谱显示薄膜透过率随Co靶电流增加而降低,退火后透过率明显提高;光谱中还出现了高自旋态Co2+(d7)电子跃迁的3个特征吸收峰,0.2 A薄膜中尤其显著。     

Fabrication of Co−Ni−P film with excellent wear and corrosion resistance by electroplating with supercritical CO2 emulsion

To avoid the defects caused by the hydrogen evolution and improve the corrosion and wear properties of the electroplated films in the traditional aqueous bath electrodeposition, a supercritical carbon dioxide (Sc-CO₂) emulsion was proposed to electrodeposite ternary nanocrystalline Co?Ni?P alloy films. Microstructure, corrosive and tribological properties of the Co?Ni?P films were investigated and compared with the ones electroplated by conventional method. The results show that the Co?Ni?P films produced with Sc-CO₂ assisted electrodeposition exhibit a more compact microstructure. The preferred orientation plane of hcp (110) for the Co?Ni?P films produced in conventional aqueous bath is changed to be hcp (100) for the one prepared in emulsified Sc-CO₂ bath. The microhardness, corrosion resistance and tribological properties of the Co?Ni?P films are substantially improved with the assistance of Sc-CO₂ in the electrodeposition bath.