退火温度对CoTiO2微结构和磁特性的影响

为了研究在稀释磁性半导体CoTiO2薄膜中不同退火温度对薄膜结构和磁性的影响,通过磁控溅射方法和原位退火工艺制备了CoTiO2薄膜样品.然后利用扫描探针显微镜以及振动样品磁强计对所制得的薄膜样品磁性和微结构的变化进行了研究.研究发现,热处理温度对薄膜的微结构和磁性能有很大的影响.扫描探针显微镜对样品的微结构分析结果表明,在400 ℃时磁性相的分布比较均匀,Co掺杂到TiO2结构当中且没有Co颗粒或团簇;振动样品磁强计测量样品的磁性能结果显示该样品具有明显的室温铁磁性.     

磁性石榴石薄膜的磁力显微镜研究

本文采用磁力显微镜（ＭＦＭ）对磁性石榴石（ＹＧｄＢｉ）３（ＧａＦｅ）５Ｏ１２薄膜的磁畴结构进行了观察研究。实验结果表明，磁性针尖的磁特性进行对石榴石ＭＦＭ图像的影响较大，而且随着针尖与样品间距的增大，磁针尖对石榴石畴结构的影响有所降低。另外，改变针尖的磁化方向，得到的石榴石磁畴结构也有所不同。     

双层细晶粒Glass／Al／BiGaDyIG薄膜的磁光性能

快速循环晶化Ａｌ／ＢｉＧａＤｙＩＧ双层膜的研究结果表明，由于晶粒细化及膜层间干涉增强效应，在０．１～１．３μｍ膜厚范围．其平均有效法拉第角比单层膜增加了０．２５°，且随循环次数增加而增大。同时．部分ＡＩ３＋离子在退火期间扩散进石榴石的八面体和四面体位，导致居里温度下降（１４０～１６１μ）。这些结果对提高石榴石磁光盘信噪比以及增大记录密度是极有意义的。     

张应力退火对玻璃包覆钴基非晶丝GMI影响

采用张应力–焦耳热方式对玻璃包覆钴基非晶丝进行退火,测量其退火后的磁滞回线和磁阻抗值,研究张应力退火对玻璃包覆钴基非晶丝静磁性能和巨磁阻抗(GMI)效应的影响。结果表明:通过处理,其各向异性场降低,其中经140MPa张应力退火的样品GMI峰值最大可达80%,所对应的磁场强度降至60A/m。随着玻璃包覆钴基非晶丝内应力的改变,导致样品壳内畴的体积增加,引起应力感生横向各向异性,从而影响GMI效应。     

内应力对玻璃包覆钴基非晶丝巨磁阻抗的影响

通过测量玻璃包覆钴基非晶丝、去除玻璃包覆层非晶丝和经直流焦耳热退火后玻璃包覆非晶丝的磁阻抗值,研究了玻璃包覆层和直流退火对玻璃包覆钴基非晶丝内应力及巨磁阻抗效应的影响。结果表明:通过处理,玻璃包覆非晶丝的GMI最大值更容易在弱磁场出现;随着淬火残余内应力的改变,导致样品壳内畴的体积增加,引起应力感生横向各向异性,从而增强GMI效应;其中经90mA直流退火的样品GMI峰值最大可达144%。     

Co-ZnO非匀质磁性半导体的磁光克尔效应研究

研究了制备态和退火态Zn1-xCoxO非匀质磁性半导体的极向克尔谱,发现通过调制样品成分和退火处理,可以大幅度调制极向克尔谱.退火后样品的磁光克尔旋转角得到显著增强,克尔角最大值达到0.72°,这是由于退火后样品变成了Co颗粒和Zn1-xCoxO磁性半导体的纳米复合体系.     

W/C.Mo/Si,W/si,Pt/si多层膜热稳定性的电镜研究

本文利用横截面电镜试样方法研究了W/C、Mo/Si、W/Si、Pt/Si四种多层膜的热稳定性。它们均生长在Si(100)衬底上,其周期数分别为125,65,288,35。透射电镜实验在H—800上进行。W/C多层膜有未退火,500℃,800℃退火0.5hr的样品,Mo/Si多层膜有未退火和500℃退火0.5hr的样品,W/Si多层膜有未退火和400℃退火0.5hr的样品,Pt/Si多层膜有未退火的样品。退火的真空度优于3×10~(-5)托。典型的衍射花样和明场像如图所示,根据衬未退火、W/Si多层膜的衍射花样及BF像。底单晶Si的衍射斑作内标可以精确地测定多层膜的周期,发现不同退火温度后其多层膜的周期不同。400℃退火后的W/     

NixSiO2（1—x）颗粒膜的光学和磁光特性研究

用磁控溅射法制备了一系列NixSiO2(1-x)样品,并对部分样品作快速退火处理,室温下采用椭圆偏振光谱仪和磁光谱仪分别为1．5－4．5eV的光子能量区了样品的复介常数谱和极向复磁光克尔谱,研究了这种金属－绝缘体型颗粒膜的化学和磁光性质,发现调整适合的金属含量或对样品作退火处理,可以观察到复介电常数的实部从正到负的连续变化,而且在一定光子能量区,其值为零;介电张量的非对角元和光学常数对其磁光克尔角的增强起重要作用。     

用于高灵敏微磁传感器的LMO膜制备与分析

采用溶胶凝胶法制备了LaMnOx(LMO)薄膜,系统研究了不同烧结温度、纵向直流磁场后退火和生长膜层数对LMO薄膜的巨磁阻抗效应的影响。结果表明,烧结温度、膜的层数以及纵向磁场后退火处理均有效提高了LMO的巨磁阻抗比,其中纵向直流磁场后退火处理提高薄膜阻抗比效果最显著,经过10Oe、400℃恒温1h磁场后退火处理后,在频率5MHz、100Oe外磁场下其磁阻抗比达15.8%,相比未后处理样品磁阻抗比提高了一倍,其对应的磁场灵敏度为0.16%/Oe。同时,实验发现磁场后退火不仅影响薄膜的巨磁阻抗比,也会改变阻抗比极大值所对应的激励频率,这一现象目前仍在探究中。     

基于4H-SiC衬底的(SiFe)C的稀磁半导体材料制备

研究了基于4H-SiC衬底的(SiFe)C的稀磁半导体材料制备方法,不同于其他人采用的MBE或MOCVD生长的方法,用离子注入的方法进行材料制备,能够与现有的集成电路工艺相兼容,用这种方法所对应的样品的居里温度320K,高于室温,具有潜在应用的价值.在制备过程中,采用了HNH退火工艺,即退火分为三个阶段,每个阶段对应不同的退火气氛、时间和温度,XRD分析表明,每个阶段都对应不同的结晶结果.另外,对应不同的Fe离子浓度,进行了实验对比,结果表明,当x=0.051的情况下对应最高的居里温度.     

A High Power Phase Shifter for Phased-Array Systems

The design of a small, lightweight, high peak and average power phase shifter is discussed. To achieve the high peak power handling, a small crystal grain technique was employed that resulted in a 14 to 1 power handling improvelment. To achieve the high average power handling, a temperature compensated garnet was used along with a novel direct dielectric liquid cooling technique. The structure used to implement the cooling causes dielectric loading of the garnet material which enhances the microwave performance of the device. The results have provided a device capable of 360/spl deg/ of continuous reciprocal phase shift while operating at signal levels of 115-kW peak, and 600-watts average power.     

Properties of the dysprosium-gadolinium gallium garnet system

Single crystals of a number of compositions of the dysprosium-gadolinium gallium garnet system were grown by the Czochralski technique. Precision lattice parameters were measured by X-ray diffraction powder methods and compositions were determined by X-ray fluorescence analysis. The precision lattice constants of the end members differ from published values and the collected data shows that the system obeys Vegard’s Law. Other physical properties are presented and compared with requirements for substrates used in the chemical vapor deposition of magnetic garnet films.     

A Low-Cost Construction Technique for Garnet and Lithium-Ferrite Phase Shifters

Low-cost construction techniques for S-band twin-slab ferrite phase shifters are presented along with an experimental comparison of garnet and lithium-ferrite materials. A 3-bit phase shifter with lithium-ferrite material, which is approximately half the price of garnet material, had a measured loss of 0.4 dB and a peak power handling of 4.5 kW.     

石榴石薄膜的液相外延(英文)

The liquid phase epitaxy for garnet films (PrGdYb)3-xBix(FeAl)5O12 on GGG substrates and their magneto-optical properties are described. The actions of the flux and each of the melt composition, the distribution principle and the growth condition are given. We have studied the relationship of the distribution coefficient and the content of Bi in the films with the growth temperature, and revealed the effects of the growth temperature, lattice mismatch and the growth rate on properties of the garnet films. Last, two peculiar properties of garnet, i. e., the intention of dislocation-free growth and boycotting self-formed nucleus of over-cold flux, are applied to discuss liquid phase epitaxy of over-cold flux.     

基于锁相循环投影的三维曲面光学检测

由一组规则栅线投影到物体表面的变化光栅,采用锁相循环解调算法解调出含有物体表面高度信息的相位。该技术的最大优势是不需传统的相位去包裹,利用该算法对二维栅线图扫描确定相位,给出了一个典型试件的实验结果和分析。     

正交复用QAM系统的定时和载波相位跟踪新算法

在数字信号传输系统中，正交复用ＱＡＭ（ＯＭＱＡＭ）是目前最有效的一种抗信道失真传输技术，但它对系统的定时偏移和载波相位误差非常敏感。本文基于高阶累积量技术，导出了一种新的ＯＭＱＡＭ系统定时和载波相位的跟踪算法。计算机仿真证实了这一理论分析结果，并同原有的Ｈｉｒｏｓａｋｉ算法做了比较     

光载波条纹自动化图像处理

本文提出一种全自动的光载波条纹处理方法，只需要一幅光载波调制的条纹图就能提取出完整的信息。先用ＦＦＴ滤波求出带有光载波的初始位相，接着用反复平均法提高位相信息的质量，然后用是小二乘法构造光载波的位相，两位相相减得出信息的位相。     

Method of testing the quality of bars of single-crystal yttrium-iron garnet

A direct method for measuring the linewidth and testing the quality of bars of single-crystal yttrium-iron garnet used in microwave delay lines is described. The technique represents a method of optimising the conventional magnetostatic delay line.     

Low-noise LD module with an optical isolator using a highly bi-substituted garnet film

We have developed a new type of laser diode (LD) module in the 1.3 ?m wavelength range coupled to a single-mode fibre with an optical isolator. The isolator comprises a highly Bi-substituted garnet film grown by liquid phase epitaxy (LPE) as a Faraday rotator. Since the garnet film is used also as a window of the hermetic seal of the LD, the reflection from the focusing lens used for fibre coupling is not allowed to return to the LD by the optical isolator. As a result, the reflection noise of the LD is prefectly suppressed. We have achieved a low-noise and compact LD module by using this construction.