真空退火Fe/Pt多层膜的结构和磁性

采用直流磁控溅射方法制备了Fe/Pt多层膜和FePt单层薄膜,并在不同温度下真空热处理得到了有序相L10-FePt薄膜.研究表明,Fe/Pt多层膜化可以降低FePt薄膜有序相的转变温度.[Fe(1.5nm)/Pt(1.5nm)]13薄膜在350℃热处理后,有序度已经增加到0.6,而且矫顽力达到了501kA/m.多层膜化促进有序化在较低的温度下进行,这主要是因为原子在多层膜界面扩散更快.     

真空退火Fe/Pt多层膜的结构和磁性

采用直流磁控溅射方法制备了Fe/Pt多层膜和FePt单层薄膜，并在不同温度下真空热处理得到了有序相L10-FePt薄膜. 研究表明，Fe/Pt多层膜化可以降低FePt薄膜有序相的转变温度.［Fe(1.5nm)/Pt(1.5nm)13薄膜在350℃热处理后，有序度已经增加到0.6，而且矫顽力达到了501kA/m. 多层膜化促进有序化在较低的温度下进行，这主要是因为原子在多层膜界面扩散更快.     

超细Co/Cu纳米多层膜磁性研究

利用磁控溅射方法制备了纳米Co/Cu多层膜。利用扫描探针显微镜(SPM)观测了其表面形貌和磁畴结构,并通过振动样品磁强计(VSM)测量了磁性。结果表明,薄膜的微结构和磁性随非磁性层厚度的变化有着非常显著的变化。超细Co颗粒构造的多层膜样品,颗粒尺寸逐渐增大,磁畴尺寸先减小后增大,最后发生明显的聚集。磁性金属和非磁性金属的比例对多层膜之间的交换耦合相互作用有显著影响。平行膜面方向上的饱和场明显小于垂直膜面方向。当体积比约为1∶80时,平行膜面方向饱和场为95.9 kA/m,垂直方向饱和场为328.1 kA/m。此时两个方向上的饱和场、剩磁、矫顽力和磁滞损耗均为最小值。     

Au/Fe磁性多层膜在离子束混合过程中的巨磁电阻效应在线研究

在离子束混合条件下,在线研究了Au/Fe磁性多层膜转变为纳米颗粒膜过程中的巨磁电阻效应,发现了不同磁场强度下的离子束混合对巨磁电阻效应影响的初步规律,测量了不同注入剂量和磁场强度下的巨磁电阻,并对结果进行了讨论。     

磁控溅射C/W纳米多层膜的微观结构分析

利用非平衡磁控溅射离子镀技术以纯钨靶和纯石墨靶作为溅射源制备了C/W纳米多层膜。采用X射线衍射（XRD）、X射线光电子能谱（XPS）和高分辨透射电子显微镜（HRTEM）对薄膜相组成及其微观组织结构进行了分析。结果表明：W含量约为9 at.%的C/W薄膜具有周期厚度约为6.5 nm的多层结构;沉积的W元素不以单质态存在,而是与碳元素反应生成了WC纳米晶;薄膜中的碳为非晶态,碳主要以sp2键类石墨态存在。     

真空退火温度对GZO/Ag/GZO三层膜性能的影响

室温下在玻璃衬底上,采用射频磁控溅射GZO(Ga掺杂ZnO)膜和离子束溅射Ag膜的方法,制备了GZO/Ag/GZO三层膜,分析了真空退火温度对样品结构、光学、电学性能的影响。结果显示:随着退火温度的升高,Ag层的结构得到明显改善,但GZO层结晶度受到了Ag扩散的影响。经过350℃退火后,样品在可见光区平均透射率达92.63%,电阻率由8.0×10–5Ω·cm降至4.0×10–5Ω·cm。     

磁控溅射Ge/Si多层膜的发光特性研究

采用磁控溅射技术,在Si(100)衬底上制备了一系列不同周期、不同Ge层厚度的Ge/Si多层膜样品.用室温光致发光(PL)、Raman散射和AFM图谱对样品进行表征.结果表明:Ge/Si多层膜中的PL发光峰主要来自于Ge晶粒,并且Ge晶粒生长的均匀性对PL发光影响较大,生长均匀的Ge晶粒中量子限域效应明显,随着晶粒的减小,PL发光主峰发生蓝移;在Ge晶粒均匀性较差时,PL发光峰强度较弱,量子限域效应不明显.     

核壳型铁钴纳米复合材料的制备及其性能

采用多元醇还原工艺和自组装技术,在微米级Fe粉表面包覆纳米Co粒子,一步法制备了一种具有核壳结构的复合磁性微球,用SEM表征了其相组成和形貌,用VSM测试了磁滞回线,初步研究了磁学性能。结果表明:用该法制备的核壳型Fe/Co纳米复合材料表面包覆致密,其比饱和磁化强度和矫顽力介于微米铁粉和纳米钴粉之间。     

C/FePt/Fe纳米薄膜的微结构和磁特性

利用超高真空磁控溅射方法制备了一系列不同C层厚度的C/FePt/Fe纳米薄膜,然后进行原位高温退火。应用X射线衍射仪(XRD)分析了样品的晶体结构,利用扫描探针显微镜(SPM)观测了表面形貌和磁畴结构,通过振动样品磁强计(VSM)测量了磁性。结果表明,薄膜的微结构和磁特性随C覆盖层厚度的变化有着非常显著的变化。C的加入使样品表面更加光滑,使10 nm厚的C覆盖层样品获得了0.3 nm的粗糙度和3.8 nm的颗粒尺寸。C覆盖层减弱了磁性颗粒间的磁偶极作用,同时减弱了磁性颗粒间的交换耦合作用,提高了L10织构的有序化程度,进而增大了样品的矫顽力,矫顽力达到了987 kA/m。     

TbDyFe-FeNi多层膜/光纤磁传感器磁敏性能实验研究

采用磁控溅射工艺制备了TbDyFe-FeNi多层膜/光纤复合结构,并搭建M-Z干涉仪磁场检测系统对复合结构的磁敏性能进行试验测试.实验结果表明,在调制磁场频率为复合结构的固有频率的条件下,系统对磁场信号感应强度最大;系统输出信号大小随调制磁场强度线性增加,添置恒定直流磁场后,系统响应信号大小明显增强.在0～48 kA/m的直流磁场范围内,干涉仪(传感臂有效长度为10 cm)信号响应灵敏度为6.05×10-5rad/(√Hz·kA·m-1);当多层膜厚度增加到5 μm时,干涉仪信号响应灵敏度变为6.07×10-5rad/(√Hz·kA·m-1).     

Magnetic Patterning of Co/Pt Multilayers by Ga<Superscript>+</Superscript> Ion Irradiation

Patterns separated by approximately 55-nm-wide lines on Co/Pt multilayers have been fabricated using a focused ion beam with a 30-keV Ga⁺ ion source. The ion irradiation allows the magnetic moment in the irradiated lines to rotate 45 deg to 90 deg toward the film plane. The in-plane magnetization component of the irradiated lines increases as the ion dose increases. The balance of incoming and outgoing flux at intersections is maintained in orthogonal patterns, while exceptions have been observed in hexagonal and triangular patterns. In all patterns, irradiated lines and adjacent unirradiated elements have no magnetic interaction.     

Study on Magnetic Domain Structure of Co/Pt Dots Array

Co/Pt multilayer dots arrays with 580-nm periodicity were fabricated using Laser interference lithog-raphy (LIL) and an ion-beam milling technique. We ob-tained uniform dots arrays with a large area by optimiz-ing the exposure parameters and improving exposure con-ditions. We obtained their shapes and magnetic domain structures and investigated using an Atomic force micro-scope (AFM) and Magnetic force microscope (MFM). The AFM and MFM images show: 1) when their size is smaller than 400nm, the dots are in single-domain state and their shape tends to be circular; and 2) when their size is greater than 400nm, the dots are in multi-domain state and they tend to form squares. The dots arrays possibly can be used in nano-scale magnetic storage.     

Dynamic Magnetic Properties of Ferroic Films,Multilayers, and Patterned Elements

Modification and control of material properties through careful manipulation of geometry on nano‐ and sub‐nanometer length scales is a cornerstone of modern materials science and technology. An exciting area in which these concepts have provided exceptional advances has been magnetoelectronics and nanomagnetism. Important scales in magnetic metals are conduction spin diffusion lengths and distances over which local moments correlate. Advanced techniques now allow for the creation of structures patterned on these length scales in three dimensions. The focus of this article is on magnetic structures whose dynamic properties can be strongly modified by ion bombardment and lithographic patterning. Examples are given of how microwave frequency properties can be tuned with external fields, how factors controlling magnetic switching can be controlled, and how manipulation of magnetic domain walls can be used to reveal new and surprising phenomena.     

Magnetic Properties of Ni/NiO Nanowires Deposited onto CNT/Pt Nanocomposites

Several nanometer‐scale technological applications rely on the promising scenario of highly anisotropic magnetic materials. Bearing this in mind, we have studied the structure, magnetic properties, and interfacial exchange anisotropy effects of unique wires of Ni/NiO synthesized using carbon nanotubes as substrates. Structural analyses of these nanocomposites in correlation with magnetic measurements show that the crystalline NiO outer shells cause an enhanced exchange bias, providing an extra source of anisotropy that leads to their magnetization stability. These Ni/NiO nanowires, with a spin‐glass‐like behavior and with their magnetic moments in a blocked state over a wide temperature range that includes room temperature, should therefore inspire further study concerning the applicability of anisotropic structures.     

聚苯胺包覆Fe3O4磁流体的制备和表征

在无氮气保护条件下用化学共沉淀法,以一定比例的Fe3+和Fe2+混合,用NH3·H2O作为沉淀剂,制备Fe3O4颗粒。再用表面原位合成法将颗粒用聚苯胺包覆,通过不断改进与优化实验条件,得到了具有一定分散性和稳定性的掺杂聚苯胺包覆Fe3O4的磁流体。