Ti衬底层对FePt颗粒膜的微结构和磁特性的影响

在室温下,应用对靶直流磁控溅射设备在普通玻璃基片上制备了FePt(30nm)/Ti(tnm)颗粒膜样品,随后,在真空中进行了原位退火.详细研究了Ti衬底层对FePt颗粒膜的微结构和磁特性的影响.X射线衍射图谱表明样品形成了较有序的L10织构,Ti和FePt形成了三元FePtTi合金.当Ti层厚度t=5 nm、退火温度Ta=500℃时,样品具有高度有序的L10织构、小的颗粒尺寸和优异的磁特性.矫顽力超过了6.7 kOe,饱和磁化强度为620emu/cc.并且具有较小的开关场分布.结果表明FePt/Ti颗粒膜系统可作为超高密度磁记录介质的候选者.     

共溅射与多层膜溅射制备FePt：Ag颗粒膜的微观结构比较

采用共溅射和多层膜溅射两种不同的溅射方式制备FePt：Ag颗粒膜。MFM和TEM微观结构观测的结果表明：与多层膜溅射制备的FePt：Ag颗粒膜相比，共溅射制备的颗粒膜具有更小的磁畴尺寸和晶粒尺寸，并且其磁畴和晶粒的分布更加均匀。这种微观结构上的区别可解释为共溅射制备的颗粒膜中Ag原子的分布更加具有随机性。对薄膜内部缺陷的研究进一步证实了该解释。     

FePt/Au多层膜的结构和磁性能研究

采用磁控溅射在SiO2<0001>基片上制备了FePt(2nm)/Au(tnm)多层膜,将其在不同温度下进行热处理。利用X射线荧光光谱仪、X射线衍射仪、振动样品磁强计和原子力显微镜对样品的结构和性能进行了研究。结果表明,沉积态样品具有超晶格结构,fccFePt和Au共格生长。经过较低温度热处理后,样品仍然保持超晶格结构。样品经400℃热处理后,开始发生有序化转变。经600℃热处理后,平行于膜面和垂直于膜面的矫顽力分别为811.7和829.2kA·m-1。当t=2.5nm时,最有利于L10-FePt相的形成。在磁化过程中,畴壁移动和磁矩转动机制共存。样品经热处理后,形成了均匀的薄膜。     

PVP对FePt纳米颗粒磁性能的影响

以乙酰丙酮铁(Fe(acac)3)和氯铂酸(H2PtCl6·6H2O)作为Fe源和Pt源,硼氢化钠(NaBH4)作为还原剂,PVP作为表面活性剂,通过化学还原法制备出单分散的FePt纳米颗粒,研究PVP对FePt纳米颗粒磁性能的影响。通过X射线衍射(XRD)仪,透射电子显微镜(TEM)和振动样品磁强计(VSM)对纳米颗粒进行表征。结果表明:PVP修饰的FePt纳米颗粒为面心立方(fcc)结构,形状近似球形且分散性良好,矫顽力为零,呈超顺磁性。当PVP与Fe(acac)3的比例为7:1时,经600℃热处理保温30min,FePt纳米颗粒从无序的fcc结构转变为有序的fct结构,矫顽力最大,可达5460A·m-1。     

中频对靶磁控溅射合成TiN/Ti多层膜

利用新型中频对靶磁控溅射技术合成了一系列TiN／Ti多层膜．考察了不同Ti间隔层对多层膜硬度和结合力的影响,分析了膜表面大颗粒和坑的形成机理;利用正交实验法和方差分析探讨了靶电流、气体压力和基体偏压对薄膜表面缺陷密度的影响,对工艺参数进行了优化．结果表明,靶电流对缺陷密度的影响最大,气体压力次之,基体偏压对缺陷密度影响最小;当靶电流I=20A、气体压力ρ（Ar＋N2）=0．31Pa、基体偏压Vbias=-16m--300V和Ti间隔层厚度x-=0．12μm时,制备出硬度HV0．2N=2250、膜基间结合力（临界载荷）Lc=48N和表面缺陷密度ρs=58mm^-2的高质量TiN／Ti多层膜．     

FePt/Cu多层膜化降低L10-FePt有序化温度

采用直流磁控溅射方法制备FePt／Cu多层膜,再经不同温度下真空热处理得到有序L10-(FePt)100-xCux薄膜．结果表明,Cu的添加可以降低FePt薄膜有序化温度．[FePt(4nm)／Cu(0．2nm)10多层膜在350℃热处理1h后,有序度增至0．6,矫顽力达到421kA／m．对插入极薄Cu层促进有序化在较低的温度下进行的热力学和动力学因素进行了讨论.     

[FePt/C]n多层膜的结构和磁学性能

采用磁控溅射方法制备FePt（50nm）和[FePt（2nm，3nm，5nm）／C（1nm）]。膜，并在550℃退火30min，研究了周期数（n）对FePt／C系列多层膜结构及磁学性能的影响。结果表明：退火后多层膜的矫顽力在总膜层厚度约为30nm时出现最大值；随着n的增大，多层膜的饱和磁化强度和晶粒尺寸均不断增大；C的加入可以有效降低晶粒间交换耦合作用。刚此可以通过控制周期数得到县仃合适的微观结构和高的磁学性能的FePt／C多层膜，从而满足超高密度磁记录介质的要求。     

调制周期对TiN/Ti多层膜组织结构和结合力的影响

为了阐明调制周期对薄膜微观组织及薄膜与基体结合力的影响,采用反应磁控溅射在Ti6Al4V基板上交替沉积了Ti层及TiN层制备了TiN/Ti多层膜。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、显微硬度仪和划痕仪测量分析了薄膜的晶体结构、微观组织、硬度以及薄膜与基体之间的结合力。研究结果表明:TiN/Ti多层膜中均存在TiN,Ti和Ti2N 3种相。TiN/Ti多层膜均以柱状晶方式生长,在调制周期较大(5层)时,TiN和Ti层的界面清晰;随着调制周期的减小(层数增加),TiN和Ti层的界面逐渐消失。与单层TiN薄膜相比,多层TiN/Ti薄膜的硬度显著提高;但随着薄膜层数的增加,多层TiN/Ti薄膜硬度略微降低。当调制周期为80nm(30层)时,薄膜与基体的结合力明显提高,达到73N。     

热处理对FePt纳米颗粒磁性能的影响

通过多重还原法制备FePt纳米颗粒,并研究不同热处理温度对其磁性能影响.XRD及TEM分析表明:所制备的FePt纳米颗粒为fcc结构,颗粒为类球形且分散性较好,尺寸在5.0 nm左右.DSC及VSM显示,高温退火处理可以使FePt纳米颗粒从无序的fcc相变成有序的fct相,随着温度的升高矫顽力变大,600 ℃时可达240 kA/m,但是在高温区(550 ℃及以上)矫顽力的变化并不明显,这主要是由高温退火过程中纳米颗粒的团聚导致的.     

NdFeB表面磁控溅射沉积Ti/Al多层膜的结构及耐腐蚀性能

采用直流磁控溅射技术在烧结NdFeB磁体表面沉积Ti/Al多层膜,并研究其结构及在NaCl溶液中的耐腐蚀性能。在Ti/Al多层膜中,Ti层为密排六方结构,成功打断了Al层(面心立方结构)的柱状晶结构生长。与纯Al膜相比,Ti/Al多层膜具有更致密的表面,且周期数增加,表面越平整致密。动电位极化曲线结果发现,纯Al膜试样的自腐蚀电流密度为1.9×10-5 A/cm-2左右,5周期Ti/Al多层膜试样的自腐蚀电流密度约为1.1×10-7 A/cm2,比纯Al膜小近两个数量级,且随着多层膜周期数的增加,其腐蚀电流密度进一步减小。这些结果表明在快速且破坏性强的腐蚀情况下,Ti/Al多层膜抗腐蚀能力比纯Al膜好,且随着周期数的增加进一步提高。NaCl溶液中长期腐蚀试验时,Ti/Al多层膜的耐腐蚀性能不如纯Al膜,这可能是由Ti层和Al层间形成原电池且多层膜应力较大导致。     

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.     

Microstructure and magnetic properties of Ti/Co/Ti films

The two series of as-deposited and annealed Ti/Co/Ti thin films were deposited by magnetron sputtering onto glass substrates at room temperature. The structural and magnetic properties of the films at room temperature were investigated as function of Co layer thickness. X-ray diffraction (XRD) profiles show Co nanograins are formed as the hexagonal-close-packed (hcp) structure. The perpendicular coercivity of the Ti(15 nm)/Co(30 nm)/Ti(15 nm) film annealed at 450 ℃ for 30 min is about 288 kA·m-1 .     

多层及交替多层NdFeB/Nd薄膜的磁性能研究

采用磁控溅射法制备了两组薄膜,经650℃退火处理后,对样品进行了XRD和VSM测试分析。结果表明：对于Mo/Nd/NdFeB/Nd/Mo多层薄膜,当NdFeB/Nd厚度比为6/5时,薄膜的矫顽力最好,平行和垂直方向的矫顽力分别为14.5kOe和10.5kOe;对于Mo/[NdFeB/Nd]n/Mo(n=2,5,8,10;NdFeB/Nd厚度比为6/5 )交替多层薄膜,当n为8时,薄膜具有最好的磁性能,平行和垂直方向的矫顽力分别为21.3kOe和16.7kOe;对于NdFeB/Nd厚度比均为6/5的薄膜,交替多层膜的综合磁性能高于多层膜。     

Microstructure and magnetic properties of Ti/Ni/Ti in dependence on Ni layer thickness

The films of Ti(15 nm)/Ni(t nm)/Ti(15 nm)(t=20, 30, 40, 50) were prepared by dc magnetron sputtering at room temperature and subsequent annealing at 400 ℃ for 30 min. Scanning probe microscope (SPM), vibrating sample magnetometer (VSM) and X-ray diffraction (XRD) were applied to study the magnetic properties and microstructure. AFM images show that small and uniform grains and some clusters appear with the increase of Ni thickness, also MFM images show that the size of domain first decreases and then increases. The coercivity reaches the maximum 48 kA·m-1 at t=30 nm. The XRD profiles show stronger fcc (111) orientation peak of Ni and weak hcp structure peaks of Ni3Ti. This results reveal that the crystal lines have the prefer orientation and achieve the ordered.     

Fe-Ga薄膜的微结构与磁性能研究

采用磁控溅射方法,以Si(1OO)为衬底在40~80 W功率下制备了Fe_(83)Ga_(17)薄膜,通过XRD、SEM、室温磁滞回线以及MFM的测量研究了不同溅射功率制备的Fe-Ga薄膜的结构、形貌、磁性能和磁畴。XRD结果表明室温下薄膜样品是bcc(11O)晶体结构。SEM观察结果表明薄膜颗粒尺寸在40~70 nm且随着功率增大,薄膜颗粒的尺寸变大,薄膜厚度增加。室温磁滞回线的测量结果表明一定范围内随着功率增大,样品的矫顽力H_c总体呈上升趋势,饱和磁化强度M_s的变化规律并不明显,剩余磁化强度M和矩形比Mr/Ms呈缓慢下降的趋势。磁畴的观察结果表明样品的磁畴为迷宫畴结构,且随着功率增大,磁畴的尺寸增大。     

Anisotropy-graded magnetic media obtained by ion irradiation of L10 FePt

We show that Ar⁺ irradiation can be used effectively to transform a chemically ordered FePt L1₀ homogeneous thin film into an anisotropy-graded composite media with tunable magnetic response. This can be exploited to produce magnetic media with high thermal stability and moderate coercivity with potential in high-density magnetic recording applications. The depth distribution of the chemical order parameter, which controls the magnetic switching mechanism of the system, has been determined by high-resolution transmission electron microscopy. The irradiation-induced modifications of the material have been modeled using Monte Carlo simulations for ion transport in solids. The magnetic properties and coupling regimes of the resulting exchange-coupled systems are discussed.     

Co/C与Co-Pt/C膜的微结构研究

利用磁控溅射方法制备Co/C和Co-Pt/C薄膜.用X射线衍射谱(XRD)和透射电子显微镜(TEM)测量样品结构和微观形貌.对Co/C和Co-Pt/C晶粒的大小进行计算,表明Co/C颗粒膜Co是以团簇的形式镶嵌在C层中的,面心立方(fcc)COPt3和面心四方(fct)Copt两个稳定有序相在Co-Pt/C薄膜中很好地...