高温结晶Ce:YIG晶体磁光性能的计算

用量子理论计算了在900℃结晶下Ce0.6Y2.4Fe5O12晶体中,Ce3+离子经晶场和交换作用劈裂后的能级和波函数,以及该晶体的法拉第旋转角,计算结果与实验符合较好.计算表明,在900℃结晶的Ce:YIG晶体的微结构与500℃结晶的有所不同,Ce3+离子的5d晶场参数发生了明显改变,电子间的超交换作用有效场减小28%.适当控制结晶温度,可改变晶体的磁光性能.     

几种稀土铁石榴石晶体的磁光性能

采用助熔剂法生长稀土铁石榴石单晶Ｙ３Ｆｅ５Ｏ１２，（ＢｉＣａ）３（ＦｅＶ）５Ｏ１２和（ＧｄＢｉ）３Ｆｅ５Ｏ１２，在近红外波段以磁光调制倍频法测量晶体的法拉第磁光旋转谱，同其它几种材料相比，（ＧｄＢｉ）３Ｆｅ５Ｏ１２晶体磁光优值大，是制作非互易光学器件较为理想的法拉第旋转晶体．     

新型磁光隔离器的研制与分析

论述了新型在线式与偏振无关薄膜光隔离器的设计、性能分析及实验结果，我们选择了ＴｂＢｉ三石榴石磁光薄膜作为４５°法拉第旋转器，两个ＹＶＯ４材料制成的楔形双折射晶体作为分束器及合束器，准直聚焦系统采用的是短焦距小像差的ｐ／４自聚焦棒，整个器件体积小，结构简单，正向损耗小于１ｄＢ，反向损耗小于３０ｄＢ。采用矩阵光学分析了光隔离器正向插入损耗和反向隔离与法拉第旋转器旋光角精度及两个楔形双折射晶体主光轴的相     

重掺杂Bi:YIG溅射薄膜的磁和磁光性能

用磁控溅射 快速退火晶化处理在YAG、Al2O3基片上制备了重掺杂Bi:YIG磁光薄膜,利用X射线衍射(XRD)、原子力显微镜(AFM)、磁光克尔仪/光学分度计、振动样品磁强计(VSM)分别研究了薄膜的微结构、磁光性能和磁性能.薄膜的饱和磁化强度为135～139 kA/m,不同基片上制备的薄膜的矫顽力不同,薄膜的法拉第角在450～610nm的光波段范围内约为3～5°/μm;当退火温度在600℃时,在两种基片上制备的薄膜透射率谱非常相似,当退火温度为800℃时,在Al2O3基片上的薄膜透射率谱将出现一个台阶.     

磁光材料及其在磁光开关中的应用

磁光材料具有种类繁多、应用广泛的特点。随着激光、光纤通信等领域的发展,各类磁光材料如磁光玻璃、磁光薄膜、磁光光子晶体和磁性液体等的发展也极为迅猛,使得应用于全光网络中的磁光开关的实现与应用成为可能。主要介绍各类磁光材料的研究进展及磁光石榴石薄膜在磁光开关中的应用进展。     

一种改善磁光式电流互感器性能的新方法

为改善磁光式电流互感器的性能,将原有磁光式电流互感器的信号处理功能单元进行了虚拟化改造。实验结果表明,虚拟仪器技术的引入,不仅可提高磁光式电流互感器信号处理单元的工作可靠性,且还能使磁光式电流互感器对电流的测量更为简便、更为精确。     

溅射氩气压对TbFeCo薄膜磁和磁光性能的影响

研究了射频磁控溅射氩气压的变化对TbFeCo薄膜的磁和磁光特征的影响，以及不同溅射氩气压下TbFeCo薄膜退火后的特性，溅射氩气压的变化通过改变表面状态影响TbFeCo薄膜矫顽力和克尔角，另外，溅射氩气压的变化会影响被溅射原子轰击薄膜的速度，从而影响TbFeCo薄膜的垂直磁各向异性，矫顽力，磁光点尔效应。     

基于磁光克尔效应的磁畴观测与处理系统

磁铁物质的基本特征是自发磁化和磁畴,磁畴的观测在磁学和磁性材料研究中具有重要作用。基于磁光克尔效应,采用自制的磁光克尔系统观测磁畴。采用先进的电荷耦合(CCD)数码成像技术,结合计算机图像处理技术(灰度处理、边缘检测等)获得磁畴图像。以铁氧体薄膜为研究对象,观测了不同外磁场作用下材料磁畴的变化情况。表明使用本系统观测磁畴方便、直观和先进。     

磁光材料的典型效应及其应用

磁光材料是一类品种繁多、应用广泛的重要的功能材料.近年来,随着激光、计算机、信息、光纤通信等技术的发展,各种磁光材料--磁光玻璃、磁光薄膜、磁性液体、磁性光子晶体和磁光液晶等发展极为迅速.本文简介了磁光效应(包括法拉第效应、克尔效应、塞曼效应和磁致双折射效应等)的基本理论以及各种磁光材料和磁光器件的研究新进展.     

Growth and Properties of CaTiO3 Single Crystal Fibers

Single crystal fibers of CaTiO₃ have been grown by the Laser Heated Pedestal Growth (LHPG) method up to several cm in length with diameters of 500–700 m. The crystals, characterized by X-ray diffraction analysis, have the distorted orthorhombic perovskite structure. Dielectric constant, dielectric loss and temperature coefficient of resonant frequency along the [101]_o and [010]_o (o means orthorhombic unit cell) direction of the crystal were investigated over the temperature range from –250°C to 100°C. The results of thermal expansion measurements up to 850°C reveal no unusual behavior associated with phase transitions. One of the modes of twinning reported by Bowman from optical analysis is confirmed by optical microscopy.     

Ag保护层对TbFeCo磁光薄膜光学性质的影响

用直流磁控溅射法制备出Ag/TbFeCo/Si(100)磁光薄膜.利用可变入射角椭圆偏振光谱仪测量了其可见光区的光学常数,给出薄膜介电函数实部和虚部随入射光子能量的变化规律,结果与经典的Drude模型相一致.同时把Ag/Si、Ag/TbFeCo/Si和TbFeCo/Si的光谱进行了比较,结果表明,由于Ag的高反射率,Ag/TbFeCo/Si的光谱更接近Ag.     

光学浮区法生长的GdFeO3单晶

正交钙钛矿结构GdFeO3材料是一种新型的磁光材料。采用光学浮区法生长磁光晶体GdFeO3,通过多次试验,生长出的晶体直径达到8mm,长度为50~80mm,晶体截面抛光后未发现明显的夹杂物等缺陷。测试结果证明光学浮区法是生长GdFeO3磁光晶体的有效方法。     

基于Allan方差的磁光玻璃型光学电流互感器噪声分析

为了更有效地提高光学电流互感器(OCT)的信噪比,针对OCT的噪声特性,提出一种基于Allan方差的噪声分析方法。应用所提方法结合光电探测器结构以及实验采集得到的噪声性质将噪声分为6类:量化噪声、高斯白噪声、1/f噪声、指数相关噪声、温度相关噪声以及正弦噪声。进一步得到含有6类噪声项的OCT随机噪声模型。针对实测数据,计算辨识了磁光玻璃型OCT随机噪声模型中各主噪声源的噪声系数。实验结果表明所提方法能有效地辨识出磁光玻璃型OCT的各个噪声项系数。通过该方法得到的噪声模型能够提高输出信噪比,为OCT应用实时滤波算法提高测量精度奠定了基础。     

磁光式电流传感器的设计与应用

磁光式互感器绝缘简单可靠,能显著降低成本,测量范围宽,无磁饱和,十分适用于高压和超高压系统中.为此,通过从模型元件的选择,到仿真实验,介绍了磁光式电流传感器的基本工作原理,测试了其灵敏性和暂态无饱和的特性.此外,磁光式电流传感器通用的数字化接口及对保护标准的兼容性,为其今后的广泛应用提供了便利.     

Ferroelectric Property and Crystal Structure of KNbO3 Based Ceramics

Rietveld refinement analysis was carried out to obtain the knowledge on the solid solution structure of the La and Fe co-doped KNbO₃ ceramics. The diffraction data was well fitted with tetragonal space group P4mm, and showed that La and Fe located at K and Nb sites in KNbO₃ perovskite, respectively. The sum of both occupancy ratios agreed almost well with the doping content. Furthermore, the effects of MnO₂ addition on the ferroelectric properties and crystal structure of the La and Fe co-doped KNbO₃ ceramics were investigated. MnO₂ addition strongly affected the ferroelectric and piezoelectric properties, because the valence of Mn ions changed from Mn^{4 +} to some extents of Mn^{3 +} and Mn²⁺, which were suggested by XAFS analysis.     

基于遗传算法的磁光记录薄膜的温度特性计算

介绍了计算磁光记录薄膜温度特性的基本原理,提出了RE-TM磁光记录薄膜温度特性计算的遗传算法.着重分析了算法实现中的关键步骤,包括适应函数的选取及定标、遗传算子的选取.实验证明该算法快速有效, 收剑性好.     

Magnetic Field and Pressure Effects on the Electrical Resistivity of Single Crystal Pr2/3(Ca,Pb)1/3MnO3

The effects of magnetic field (H) and pressure (P) on the temperature (T) dependence of electrical resistivity () are reported for a new manganese-containing compound, Pr_2/3(Ca,Pb)_1/3MnO₃, which was grown in single-crystal form by a flux method. The material was found to order magnetically with applied-field strength below 175 K, but have zero remanence (M _R ) as HO, i.e., there was no spontaneous magnetization (M _S ), only field-induced magnetization (M _i ). A zero-field insulator to metal transition occurred at 146 K and this transition temperature (T _1M ) was found to increase with increasing field strength. The change in resistivity with field, _O-_H, normalized with respect to _H, was 900% at 146 K and H = 5T. On application of hydrostatic pressure the zero-field resistivity decreased by 200%/GPa above room temperature. The electrical transport observed was consistent with a thermally-activated process, and this process was found to be relatively independent of pressure (0–4 GPa) in the temperature region (300 K–400 K) studied.