钙钛矿氧化物La0.3Ca0.7MnO3的磁性质

采用固相反应法制备了样品La0.3Ca0.7MnO3. 通过测量样品的M-T曲线、 M-H曲线和ESR曲线, 研究了La0.3Ca0.7MnO3的磁性质. 结果表明 在262 K时形成电荷有序相(CO相). 当T＞262 K时, 表现为顺磁;当T＜190 K时, 表现为长程反铁磁(在AFM本底中存在少量FM成分);从262～190 K(TCO), 随温度降低在电荷有序态下从顺磁向反铁磁转变.     

新型钴基非晶态合金屏蔽材料的磁性研究

研究了不同退火条件下，新型屏蔽材料钴基非晶态合金Co66Fe4Ni1Si15B14的磁阻抗比（MIR）和磁导率比（PR）。采用了两步冷却法（F＆W），通过协同降低内热应力和磁有序，提高了样品的初始磁导率。研究结果表明，F＆W法试样的初始磁导率（μi）比单独用熔炉冷却法（FC）和水淬火法（WQ）分别提高了50％和100％。通过测量试样的MIR和PR，研究了试样软磁性的退火效应，3．1MHz下FC法试样和WQ法试样在420℃退火温度下具有比F＆W法更优越的软磁性。     

铝电解槽三维电热场耦合分析

利用有限元软件ANSYS,建立了包含摇篮架在内的铝电解槽完整的有限元模型。针对沈阳铝镁设计研究院设计的300kA铝电解槽,进行了三维电热场耦合分析。模拟结果说明所建模型是正确的,为电解槽的优化设计和改造提供参考。     

旋转管式膜器处理含油废水的研究

用常规方法处理乳化油污水比较困难,存在不同的问题,膜分离技术处理乳化油污水具有分离精度高,无二次污染,过程无相变等优点。     

FeCrCo可加工永磁半硬磁特性的应用研究

随着科技的进步,各个领域对FeCrCo合金的磁性能范围提出了更高的要求,尤其对它的半硬磁特性有很大的需求.探讨了获得FeCrCo合金半硬磁特性的理论依据及方法,通过实验,该方法生产的FeCrCo合金系列的半硬磁特性性能稳定,可作为优秀的永磁材料及半硬磁材料使用.     

换向方式对蓄热式加热炉内温度场和浓度场的影响

利用大型软件CFX4.4建立了高温蓄热式加热炉内的温度场和浓度场的数学模型.分析讨论了不同换向方式对蓄热式加热炉内温度场和浓度场的影响.     

Magnetization Reversal by Electrical Spin Injection in Ferromagnetic (Ga,Mn)As-Based Magnetic Tunnel Junctions

We report current-induced magnetization reversal in a ferromagnetic semiconductor-based magnetic tunnel junction (Ga,Mn)As/AlAs/(Ga,Mn)As prepared by molecular beam epitaxy on a p-GaAs(001) substrate. A change in magneto-resistance that is asymmetric with respect to the current direction is found with the excitation current of 10⁶ A/cm². Contributions of both unpolarized and spin-polarized components are examined, and we conclude that the partial magnetization reversal occurs in the (Ga,Mn)As layer having smaller magnetization with the spin-polarized tunneling current of 10⁵ A/cm².     

Spin Polarization by Tilted Magnetic Field in Wide Ga1?xAlxAs Parabolic Quantum Wells

Wide parabolic wells can be created by properly controlling the Al content during the growth of successive Ga_1–xAl_xAs thin layers. Under a tilted magnetic field these systems present interesting transport properties, which are associated to their composition dependent g-factor. We present an exact solution for the eigenstates of an electron gas inside such a quantum well. We calculate the renormalized cyclotron frequencies as functions of the angle of tilt, as well as the density of states, and the Fermi level. We discuss the conditions for the existence of spin-polarized charge.     

Analysis of a Gyroscope＇s Rotor Nonlinear Supported Magnetic Field Based on the B-Spline Wavelet-FEM

A supported framework of a gyroscope＇s rotor is designed and the B-Spline wavelet finite element model of nonlinear supported magnetic field is worked out. A new finite element space is studied in which the scaling function of the B-spline wavelet is considered as the shape function of a tetrahedton. The magnetic field is spited by an artificial absorbing body which used the condition of field radiating, so the solution is unique. The resolution is improved via the varying gradient of the B-spline function under the condition of unchanging gridding. So there are some advantages in dealing with the focus flux and a high varying gradient result from a nonlinear magnetic field. The result is more practical. Plots of flux and in the space is studied via simulating the supported system model. The results of the study are useful in the research of the supported magnetic system for the gyroscope rotor.     

Magnetic Perovskite Superlattices Grown by Pulsed Laser Deposition

Magnetic multilayers of (SrRuO₃) _m (SrMnO₃) _n were grown artificially using the pulsed laser deposition technique on (001)-oriented SrTiO₃ substrates. The temperature and magnetic field dependent reisistivity of the superlattices consisting of ferromagnetic (FM) SrRuO₃ and antiferromagnetic (AFM) SrMnO₃ are studied as a function of the SrRuO₃ unit cells. We observed a pinned/biased moment instead of the biased field in the superlattices and we redefine the structure as AFM/FM(Pin)/FM(Free)/FM(Pin) units below a critical field.