Magneto-Optical Parameter Q for Structures with Uniaxial Optical Anisotropy

Journal of Experimental and Theoretical Physics - This paper is devoted to the development of reflection magneto-optical ellipsometry. We have solved the inverse problem for structures with...     

Investigation of the Domain Structure of Co-Based Microwires by Magneto-Optical Indicator Films Method

Physics of the Solid State - The investigation of domain structure of Co-based microwires with negative magnetostriction was provided by magneto-optical method of indicator films. The thickness of...     

MnBiAl薄膜的磁光及磁性能研究

用真空电子束蒸发制备了MnBi_xAl_0.15薄膜.当0.4≤x≤0.7时,MnBi_xAl_0.15薄膜的Kerr角与MnBi_x薄膜相比有显著增大;而当x＞0.7时,MnBi_xAl_0.15的Kerr角则比MnBi_x的要不,633nm波长测量时,MnBi_{0.5Al0.15的Kerr角为2.75°,而相对应的MnBi0.5薄膜只有1.56°.MnBi05Al0.15薄膜的室温饱和磁化强度Ms为3×10⁵A/m,比MnBi0.5薄膜的Ms(4×10⁵A/m)要小.推测当0.4≤x≤0.7时,Al可能部分占据Bi空位和部分取代Mn位,由于晶格收缩使得Mn 3d电子与Bi 6p电子的杂化概率增大,从而导致其Kerr效应增强. 关键词：}     

Cu添加石榴石磁光薄膜读,写性能的研究

用热分解法在玻璃衬底上制备了Ｃｕ添加的Ｂｉ，Ａｌ：ＤｙＩＧ磁光薄膜，对其静态读、写性能进行了详细的研究。Ｃｕ添加的薄膜可获得高的矫顽力和好的矩形化，对记录畸起着稳定的作用。同时，适量Ｃｕ的添加可起到细化晶粒的作用，对减少晶界噪声有利。     

Anisotropy of Critical Fields in MgB2： Two-Band Ginzburg-Landau Theory for Layered Superconductors

The temperature dependence of the anisotropy parameter of upper critical field γHc2(T)=H_{c2}^||(T)/H_{c2}^{\bot}(T) and London penetration depth γ_λ(T)=λ_{\perp} (T)/λ_{\bot} (T) are calculated using two-band Ginzburg-Landau theory for layered superconductors. It is shown that, with decreasing temperature the anisotropy parameter γ_{H_{c2}}(T) is increased, while theLondon penetration depth anisotropy γλ(T) reveals n opposite behavior.Results of our calculations are in agreement with experimental datafor single crystal MgB₂ nd with other calculations. Results of an analysis of magnetic field H_c1 in a single vortex between superconducting layers are also presented.     

Preparation of Fe/Pt Films with Perpendicular Magnetic Anisotropy

We have investigated the microstructures and magnetic properties of L1₀ ordered equi-atomic FePt thin films prepared by ion beam sputtering and subsequent annealing. It is observed from X-ray reflectivity and X-ray diffraction measurements that the mixing at Fe/Pt interfaces starts to occur with annealing and leading to the FePt alloy phase formation. The rapid increase in the coercivity values above 275°C, obtained from vibrating sample magnetometer (VSM) measurements, confirms the formation of the ordered L1₀ FCT FePt phase.     

Heat-Treatment Induced Magnetic Anisotropy of GaMnSb Films

Conditions and mechanisms of controlled variation of the magnetic anisotropy of GaMnSb films containing magnetic MnSb nanoinclusions by means of heat treatment have been determined. For this purpose, the temperature and magnetic-field dependences of the magnetic moments of samples before and after thermal annealing were measured using a SQUID magnetometer. It is established that the heat treatment of GaMnSb films leads to a significant increase in the values of characteristics determined by the magnetic anisotropy, including the growth of blocking temperature (from 95 to 390 K) and the magnetic anisotropy field (from 330 to 630 Oe). Results of transmission electron microscopy investigation indicate that a change in the magnetic anisotropy of GaMnSb films as a result of their thermal annealing can be related to a transition of the crystalline structure of magnetic MnSb nanoinclusions from hexagonal (space group P6₂/mmc) to cubic (space group F-43m).     

非线性磁光效应用于测量磁光阱四极磁场的方案

为了研究磁光阱冷原子团所在区域的磁场大小,从而得出磁场零点附近磁场的微弱变化及其分布。提出利用右旋圆偏振作为探测光场穿过冷原子,根据左右旋圆偏振光场引起的跃迁几率的不同,导致穿过冷原子团零点前后探测场跃迁几率的变化,用来计算零点附近由冷原子团引起的非线性磁光效应,通过这一效应推导出旋转角随磁场大小的变化,从而获得了磁光阱四极磁场零点附近数量级达到10^-13T的磁场值。利用这一效应,同时在理论上获得了不同于以往理论及实验的双峰色散曲线。     

The Magneto-Optical Voigt Parameter from Magneto-Optical Ellipsometry Data for Multilayer Samples with Single Ferromagnetic Layer

Physics of the Solid State - Calculations of the magneto-optical Voigt parameter Q were carried out using various models of reflecting media for thin films Fe|SiO2|Si(100) samples using the data of...     

Capabilities of Magnetic Pseudoresonance in Studies of Thin Ferromagnetic Films with Uniaxial Magnetic Anisotropy

Technical Physics - Possibilities of magnetic pseudoresonance (a non-resonance peak of magnetic susceptibility) were studied and compared with the ferromagnetic resonance (FMR) in measuring the...     

Optical and Magneto-Optical Properties of Multilayer Nanosized [Co/TiO2]n Films

Physics of the Solid State - Abstract—The optical and magneto-optical properties of the metal–dielectric multilayer [Co/TiO2]n structures with 2–4-nm-thick layers prepared on a...     

Structural Anisotropy of Amorphous Silicon Films Modified by Femtosecond Laser Pulses

It is demonstrated that the surface-relief orientation in the form of one-dimensional gratings with a period of 1.20 ± 0.02 μm formed under processing of hydrogenated-silicon films by femtosecond laser pulses (1.25 μm) with an energy density of 0.15 J/cm² is determined by the direction of the polarization vector of the radiation and total laser exposure. Based on the results of the analysis of Raman spectra, the presence of a nanocrystalline phase of silicon with a volume fraction between 15 and 67% (depending on processing conditions) is detected. The observed processes of micro- and nanostructuring are caused by excitation of the surface plasmon–polaritons and nanocrystallization in the near-surface region in the field of high-power femtosecond laser pulses, respectively. In addition, formation of polymorph modifications of silicon Si-III and Si-XII under femtosecond laser processing with a number of pulses exceeding 500 is discovered. Anisotropy of the Raman signal for the above polymorph modifications is revealed.     

Visualization of Dynamic Vortex Structures in Magnetic Films with Uniaxial Anisotropy (Micromagnetic Simulation)

Three-dimensional computer simulation of dynamic processes in a moving domain boundary separating domains in a soft magnetic uniaxial film with planar anisotropy is performed by numerical solution of Landau-Lifshitz-Gilbert equations. The developed visualization methods are used to establish the connection between the motion of surface vortices and antivortices, singular (Bloch) points, and core lines of intrafilm vortex structures. A relation between the character of magnetization dynamics and the film thickness is found. The analytical models of spatial vortex structures for imitation of topological properties of the structures observed in micromagnetic simulation are constructed.     

A General Method for Constrained Analysis of Fluorescence Anisotropy Decay: Application of the Steady-State Anisotropy

Time-resolved fluorescence anisotropy is an invaluable method for investigating the internal and rotational dynamics of biomolecules. The range of rotational motions detectable by anisotropy decay is limited by the fluorescence lifetime; typically, a depolarizing motion may be resolved if the associated correlation time is between 0.1 and 10 times the intensity decay lifetime. To extend that range and to improve the recovery of anisotropy decay parameters, a general analytical method has been developed. This procedure utilizes a modification of Lagrange multiplier methods to constrain the values of the iterated kinetic parameters during nonlinear least-squares analysis of anisotropy decay data. The form of the constraint equation is derived from the classic relationship between the decay parameters and the steady-state anisotropy, which can be simply and accurately measured. Application of the constraint to analyses of synthetic data sets increased the accuracy of recovery by decreasing the uncertainty in the iterated parameters. The constraint also enabled the accurate recovery of correlation times that were a factor of 30 greater than the fluorescence lifetime, although it did not improve recovery of correlation times that were much shorter than the lifetime. Using this technique, it should now be possible to characterize the dynamics of larger macromolecules and assemblies than those that can currently be studied by fluorescence anisotropy decay.     

蓝光磁光盘的优化设计与分析

以TbFeCo作为蓝光磁光盘的记录介质，需要对传统磁光盘热、光学结构进行改进以提高载噪比。利用光学特征导纳矩阵法对改进结构的磁光盘膜层进行了优化设计，得到了较好的匹配结果；并通过热学计算得到了记录膜体温度分布，从理论上证明了新结构的优越性。     

FMR Investigation of the Magnetic Anisotropy in Films Synthesized by Co<Superscript>+</Superscript> Implantation into Si

Thin ferromagnetic films with the uniaxial magnetic anisotropy were synthesized by Co⁺ implantation into single-crystal silicon in the magnetic field. It was concluded that the formation of the induced magnetic anisotropy is due to the directional atomic pair ordering (Neel–Taniguchi model). The synthesized films were studied by the ferromagnetic resonance (FMR) method in the temperature range from 100 to 300 K. The FMR linewidth is almost independent of temperature, which is in agreement with the Raikher model describing the magnetic resonance of uniaxial magnetic particles. It is found that the temperature dependence of the anisotropy constant is linear. This dependence can be associated with the difference in the coefficients of thermal expansion of the Si (111) substrate and the ion-beam-synthesized cobalt silicide films.     

应力各向异性对铁磁/反铁磁双层薄膜磁性质的影响

 采用铁磁共振方法,研究了交换各向异性和应力各向异性对铁磁/反铁磁双层薄膜性质的影响。结果表明：界面交换作用导致单向各向异性,应力各向异性对材料的磁化难易程度有较大影响。在外磁场方向接近应力场方向时,共振频率向高值方向移动,其它区域共振频率则向低值方向移动。对频率线宽而言,接近应力场方向,频率线宽加宽,其它区域频率线宽则变窄。此外,当磁场变化时,应力的存在使得共振频率向低值方向移动,尤其在β＝π方向情况较为复杂,在弱场范围出现了两个区域：即在某磁场范围内,共振频率向高值方向移动,且频率线宽加宽;而其它范围的共振频率（线宽）是向高值方向移动（加宽）还是向低值方向移动（变窄）,取决于外磁场的相对强弱。     

A Geometric Interpretation of the Effective Uniaxial Anisotropy Field in Magnetic Films

It is shown that the effective uniaxial anisotropy field that is usually applied in thin magnetic films (TMFs), which is noncollinear to the magnetization vector, is insufficient for deeper understanding of these processes, although it explains many physical processes in films. The analysis of the magnetization discontinuity in films under certain conditions yields the component of the effective uniaxial anisotropy field collinear to the magnetization vector. This component explains the magnetization discontinuity and allows one to speak of the total effective uniaxial anisotropy field in TMFs.     

利用羊八井中子监测器研究宇宙线的太阳日周期变化

通过对宇宙线周期变化研究可以得到宇宙线产生和传播区域的重要信息,是宇宙线长期研究的重要热点问题。利用位于西藏羊八井(地磁截止刚度:14.1 GeV) 的中子监测器2006 至2011年的观测数据,研究宇宙线的太阳日周期变化。在对中子监测器观测数据进行气压修正后,通过Lomb-Scargle 傅立叶变换法对修正后的数据进行周期分析,发现宇宙线计数率存在超过地球公转运动Compton-Getting 效应的太阳日周期变化,该周期变化可能是地球公转效应和宇宙线传播物理过程调制效应以及剩余气象效应的叠加。计算分析了1 日周期信号的振幅和初相位随时间的变化,发现1 日周期变化的初相位存在较为明显的年周期变化规律,这可能是地球公转和自转合成运动的结果;1 日周期变化幅度在2010 年后出现增大趋势。这些结果对宇宙线周期变化和各向异性的研究具有重要参考意义。With the study of the cosmic rays' solar diurnal variation we can get the important information about Cosmic Ray's production and propagation. It's important issues of cosmic rays' studies. We analyze the temporal variation of cosmic rays rate observed with the Yangbajing neutron monitor during 2006 to 2011, and nd semidiurnal and diurnal period signals included in the rates of cosmic rays with vertical rigidity equal to 14.1 GV. We have checked the time dependence of the phase and the amplitude of semidiurnal and diurnal anisotropy, and nd that the phase of diurnal signal varies yearly, it could be a synthetic movement of the earth's rotation and revolution. The amplitude before 2010 is obvious smaller than that after 2010. These results are of great reference value for studying the anisotropy and time variation of cosmic rays.