Fe45Ag55颗粒膜的磁光尺寸效应

用离子束溅射方法制备了Fe₄₅Ag₅₅颗粒膜样品,通过X射线衍射和磁性及磁光测量研究了它们在不同退火条件下的结构和磁性.结果表明其磁光效应与颗粒尺寸密切相关. 关键词：     

反射型磁光多层膜隔离器工作稳定性的研究

与单纯的磁光晶体相比,由磁光介质与电介质周期性或准周期性排列构成的一维磁光光子晶 体能够显著增强磁光效应,可以用于实现小尺度的磁光隔离器,从而大大减小器件的尺寸. 给出更为一般的可用于求解斜入射情况下偏振光在各向异性介质中传播时的传输矩阵方法, 并用这种方法在波长为1053μm处,针对两种“三明治”型的反射磁光多层膜隔离器的 结构,具体讨论了器件应用时入射角度及工艺制作时膜层制备厚度对它们工作稳定性的影响 .发现中心磁光介质夹层较厚的结构具有膜层数目少、工作稳定性好的优点. 关键词： 光隔离器 磁光效应 一维光子晶体     

利用FePt/Au多层膜结构制备垂直磁记录L10-FePt薄膜

利用磁控溅射方法在100℃的MgO单晶基片上制备了［FePt/Au］₁₀多层膜,并研究了采用FePt/Au多层膜结构对FePt薄膜的有序化温度、矫顽力（H_C）、垂直磁各向异性、晶粒尺寸以及颗粒间磁交换耦合作用的影响.磁性测试结果表明：FePt/Au多层膜在退火后具有较高的H_C、良好的垂直磁各向异性、较小的晶粒尺寸且无磁交换耦合作用.截面高分辨电镜分析表明：Au可以缓解MgO和FePt之间较大的晶格错配,从而促进薄 关键词： 0-FePt薄膜')" href="#">L1₀-FePt薄膜 有序化温度 垂直磁各向异性 磁交换耦合作用     

多缺陷结构的一维磁光多层膜隔离器

由磁光介质（M）和电介质（G）周期性排列构成的磁光光子晶体会出现很强的光 局域性，最近用它来实现磁光隔离器引起人们广泛的兴趣.给出了一种可用于计算 偏振光在各向异性介质传播问题的传输矩阵方法.并用该方法计算了对称多缺陷结构磁光多 层膜隔离器的光学性质，发现随着缺陷数目的增多，旋转角及透过率的频谱响应得到改善. 当缺陷增加到一定数目时，不需要额外的反射层即可实现反射型磁光隔离器的要求. 关键词： 光隔离器 磁光效应 多层膜 光子晶体     

利用FePt/Au多层膜结构制备垂直磁记录L10-FePt薄膜

利用磁控溅射方法在100℃的MgO单晶基片上制备了[FePt/Au]10多层膜,并研究了采用FePt/Au多层膜结构对FePt薄膜的有序化温度、矫顽力(HC)、垂直磁各向异性、晶粒尺寸以及颗粒间磁交换耦合作用的影响.磁性测试结果表明:FePt/Au多层膜在退火后具有较高的HC、良好的垂直磁各向异性、较小的晶粒尺寸且无磁交换耦合作用.截面高分辨电镜分析表明:Au可以缓解MgO和FePt之间较大的晶格错配,从而促进薄膜的垂直磁各向异性;同时,采用FePt/Au多层膜结构增加了FePt/Au界面能、应力能以及Au原子在薄膜中的扩散作用,促进了薄膜的有序化,从而有效降低了有序化温度,并且大幅度提高其HC.此外,Au原子部分扩散到FePt相的边界处,起到抑制FePt晶粒生长、隔离FePt颗粒的作用,从而显著降低了FePt晶粒的尺寸和颗粒间磁交换耦合作用.     

利用表面磁光克尔效应监测Ni薄膜生长的物相转变

利用磁控溅射方法制备了不同厚度和退火处理的Ni薄膜.表面磁光克尔效应研究表明:冷基底无退火处理的Ni薄膜为软磁性,退火处理的Ni薄膜为铁磁性质,且无退火处理的Ni金属膜磁性随膜厚的增加而增强.分析认为,冷基底条件下Ni膜是非晶态生长,且膜内存有大量缺陷,经退火处理的Ni膜发生了重融再生长,形成了大颗粒结晶,膜内晶粒内缺陷大量消失.     

反射型磁光多层膜隔离器的频率响应及宽容性研究

通过传输矩阵法分析了材料介电常数的变化对于单缺陷结构的磁光多层膜隔离器性能的响，并提出了一种多缺陷结构的磁光多层膜结构.同单缺陷结构相比，多缺陷结构的旋转角的频谱响应带宽有很大增加，对于材料介电常数变化的宽容性得到了一个数量级的提高.同时这种多缺陷的结构对于膜层厚度的变化和入射角度也有很好的宽容性. 关键词： 光隔离器 磁光效应 一维光子晶体     

退火对Co35(SiO2)65颗粒膜巨磁电阻效应的影响

采用多靶离子束溅射镀膜机制备了一系列不同退火温度的Co₃₅(SiO₂)₆₅（体积百分数）颗粒膜样品,发现样品的巨磁电阻效应随着退火温度T_a的升高而单调下降.应用磁力显微镜对样品的磁结构进行了观测,发现随着退火温度的升高,近邻的Co颗粒的磁矩倾向于平行排列,形成磁畴结构,从而导致Co₃₅(SiO₂)₆₅颗粒膜巨磁电阻效应单调下降. 关键词：     

百年磁光效应的新认识

磁光效应反映了光与磁之间最基本的相互作用,是凝聚态物理学中一个古老且迷人的研究议题.自1846年发现磁光法拉第效应至今,关于磁光效应的研究已经历了一个半世纪之久.文章将介绍磁光效应领域的三项最新研究进展.其一,磁光效应被发现可以存在于净磁化强度为零的反铁磁中,且表现出对矢量自旋手性的强烈依赖性.其二,磁光效应的物理起源...     

磁光光纤中光脉冲的非线性传播特性研究

根据光纤中磁光效应与非线性效应的微扰理论,推导了磁光光纤中光脉冲的非线性耦合模方程,比较了修正的分步傅里叶算法中磁光效应的时域和频域处理方案,表明了在步长足够小的情况下,两种方案的结果一致.分析了磁光效应、光纤非线性以及色散对光脉冲传输特性的影响,通过改变磁光耦合强度,不但可以灵活控制脉冲形状,还可以改变非线性引起的频率啁啾大小,有助于实现基于光脉冲展宽的动态整形功能.本文给出的理论分析方法,有助于开发可用于光纤通信、光纤传感等领域的基于非线性磁光光纤的新型磁光信息处理器件.     

PtMn/Co多层膜的磁光特性研究

采用磁控溅射法制备了一系列的Mn掺杂的PtMn/Co多层膜.通过测量得到的磁光常数和光学常 数,计算介电张量的对角元和非对角元,得到在掺杂较大时,克尔角的变化是由于介电张量 的非对角元引起的;在掺杂量较小时,克尔角的变化是由介电张量的对角元和非对角元以及 光学常数的变化引起的.     

Magneto-optical Kerr effect (MOKE) of the rare-earth silicide ErSi2 using ab-initio calculations

We present a computational method for the ab-initio study of the magneto-optical quantities using the augmented plane wave plus local orbitals (APW+lo) method. The calculations are performed within the local-density (LDA) approximation. In the present paper, the optical conductivity is the basic quantity for the evaluation of the magneto-optical Kerr effect (MOKE). Thus it is well described and calculated. Considerable work has been performed on the magneto-optical Kerr effect using experiments, however, no experimental or theoretical work has been investigated on rare-earth silicide ErSi₂, in particular using ab-initio method. Our results consist a prediction.     

Magneto-optical parameters of Co90Fe10 and Co50Fe50 ferromagnetic thin films for 1.3 μm integrated isolator

In order to optimize a 1.3 μm integrated optical isolator using a CoFe alloy for the non-reciprocal magneto-optical (MO) transverse Kerr effect, we have measured the optical and magneto-optical indices of Co₉₀Fe₁₀ and Co₅₀Fe₅₀ alloys grown in the Al₂O₃/Al/CoFe/GaAs multilayer structure. The optical reflectivity and MO rotation and ellipticity measurements were performed at variable incidence angle and s and p polarization of the incident light. In order to determine the optical and MO indices, the experimental data were fitted using a Matlab implementation of a standard multilayer Yeh formalism including multiple reflections. This original procedure allows precise determination of the optical and MO indices of CoFe alloys.     

Magnetic and magneto-optical properties of epitaxial cobalt films grown on a corrugated CaF<Subscript>2</Subscript>/Si surface

The magnetic properties of CaF₂/Co/CaF₂(110)/Si(001) heterostructures fabricated by molecular-beam epitaxy and having a corrugated CaF₂ buffer surface were studied. The optical and magneto-optical properties of these structures reflect the C _2v symmetry of the corrugated structure surface. The studies of hysteresis loops using the longitudinal and transverse magneto-optical Kerr effects under oblique light incidence and of magneto-optical phenomena under near-normal light incidence demonstrate that the corrugated structure surface leads to optical and magneto-optical anisotropies. The magnetization of such structures occurs via coherent magnetization rotation over a wide magnetic-field range. The magnetic anisotropy of these structures is described using a Gaussian distribution of easy axes of magnetization in cobalt granules about the direction parallel to the groove direction. The asymmetry of hysteresis loops of the rotation of the plane of polarization detected under oblique and normal light incidence is shown to be related to the contributions to the effective film permittivity that are quadratic in the magnetic moment.     

双层膜极向Kerr效应的增强与其本征值之间的关系

应用相干光迭加的普遍原理，从理论上导出了双层膜情况下，介质增强后的极向Ｋｅｒｒ角（θ_k）与磁光介质本征的极向Ｋｅｒｒ角（θ⁰_k）之间关系的解析表达式，指出了光经玻璃衬底面入射到磁光介质时测量的Ｋｅｒｒ角θ_k与磁光介质本征Ｋｅｒｒ角θ⁰_k的不同，提出了一种简便的测量θ⁰_k的方法，并讨论了Ｋｅｒｒ角θ_k介质增强的物理原因，从理论上导出了等离子体吸收边情况下，双层膜的Ｋｅｒｒ角θ_k增强的关系式。 关键词：     

Growth and properties of ferromagnetic In1−xMnxSb alloys

We discuss a new narrow-gap ferromagnetic (FM) semiconductor alloy, In_1−xMn_xSb, and its growth by low-temperature molecular-beam epitaxy. The magnetic properties were investigated by direct magnetization measurements, electrical transport, magnetic circular dichroism, and the magneto-optical Kerr effect. These data clearly indicate that In_1−xMn_xSb possesses all the attributes of a system with carrier-mediated FM interactions, including well-defined hysteresis loops, a cusp in the temperature dependence of the resistivity, strong negative magnetoresistance, and a large anomalous Hall effect. The Curie temperatures in samples investigated thus far range up to 8.5 K, which are consistent with a mean-field-theory simulation of the carrier-induced ferromagnetism based on the 8-band effective band-orbital method.     

Cavity enhancement of the magneto-optic Kerr effect in glass/Al/SnO2/PtMnSb/SnO2 structure

The cavity enhancement effect of the transparent semiconductor SnO₂ on the magneto-optical Kerr response of the glass/Al/SnO₂/PtMnSb/SnO₂ multilayer structure has been investigated using a matrix method. It has been demonstrated that device optimization leads to large Kerr rotation and figure of merit (FOM) with a vanishing ellipticity in the visible portion of the electromagnetic spectrum, especially at short wavelengths. This optimization is of interest in view of optical data storage technology. Using numerical simulations, we have also shown that in the optimum condition, the device readout parameters behave smoothly against the design variables.     

Optical and magneto-optical properties of Fe<Subscript>4−x</Subscript>Co<Subscript>x</Subscript> (x = 1–3)

We report a systematic study of the electronic, optical, and magneto-optical properties of the Fe_4−xCo_x (x = 1–3) compounds using the full-potential linearized augmented plane waves (FPLAPW) method within the local spin density approximation (LSDA). Pure Fe (x = 0) and Co (x = 4) have also been studied, the latter in hcp as well as bcc structure, to offer a better comparison. A good agreement is obtained between calculated optical conductivity spectra and experimental data. We note that the magneto-optical properties of these compounds are found to be more akin to those of bcc Co (which has MOKE very similar to that of bcc Fe) than to those of hcp Co. This shows strong impact of the environment on the MOKE of these compounds. With respect to the elemental values, the magnetic moments at Fe sites are found to be larger in general, while those at Co sites are almost the same. However, interestingly, despite their larger magnetic moment, the Kerr rotation remains comparable to that of bcc Fe for most of the energy range. The origin of Kerr spectra has been explained in terms of optical transitions.