共查询到20条相似文献,搜索用时 156 毫秒
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用磁控溅射法制备了GdFeCo/DyFeCo交换耦合两层薄膜,对交换耦合两层薄膜变温磁化方向进行了研究.结果表明读出层GdFeCo随温度上升从平面磁化转变成垂直磁化,转变过程中主要受饱和磁矩(Ms)的影响.在GdFeCo的补偿温度附近,读出层的磁化强度近于零,退磁场能减小,并在交换耦合的作用下,使读出层的磁化方向发生转变,制备的交换耦合两层薄膜具有中心孔磁超分辨效应.
关键词:
磁光记录
交换耦合两层薄膜
磁化 相似文献
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给出了任意倾斜偏置磁场作用下相位失配时微波静磁波与导波光的磁光耦合方程,分析了相位失配对导波光衍射效率及其衍射方向的影响.计算了YIG薄膜波导中静磁反向体波与导波光非共线作用的Bragg衍射效率, 传统磁化时计算结果与实验结果一致.计算表明,与传统磁化情形相比,适当的偏斜磁场可使导波光衍射效率提高6dB以上;当导波光入射角保持不变时,由磁场方向改变引起的相位失配对衍射效率的影响不大.因此,优化偏置磁场方向是改善磁光Bragg器件衍射性能、提高磁光带宽的有效方法.
关键词:
磁光效应
Bragg衍射
静磁波 相似文献
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起始磁化曲线作为铁磁材料磁学特性的重要表征, 研究其获取方法具有重要意义. 现有方法采用随时间变化磁场作为激励磁场, 通过改变激励磁场大小, 逐步改变试件内的磁场及磁感应强度并进行测量以得到起始磁化曲线, 效率较低, 准备繁琐. 为此, 本文从基本的磁学物理定理出发, 提出一种基于时空变换的起始磁化曲线推算方法. 该方法以细长棒状试件或环形试件作为被测试件; 采用恒定磁化在被测试件内产生空间变化磁场作为激励磁场; 通过测量试件表面的磁场值来推算试件内磁场值, 从而获取铁磁材料起始磁化曲线. 直流线圈恒定磁化环形和棒状试件仿真实验验证了该方法的理论正确性. 进一步地, 考虑实际应用限制因素的推算结果表明了该方法在实际应用中是可行的, 可为探索新的起始磁化曲线测量方法提供理论指导. 相似文献
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磁介质磁化的研究方法与电介质的极化研究方法类似,学习本章时注意和电介质的极化对比是有益的。 磁介质放在外磁场B0中→磁介质要磁化→磁化的结果是在磁介质内部或表面产生磁化电流(I’,i’)→磁化电流激发一个附加磁场B’→空间各处的磁场 B= B0 × B' 磁化完成后,磁化电流不随时间变化,所以B’是稳恒磁场.由于B0是稳恒磁场,所以有磁介质存在时的总磁场B为稳恒磁场,因此稳恒磁场的规律对B完全适用,即: 1 磁介质磁化的微观机制 一、顺磁质的磁化.(对比电介质中有极分子的取向极化) 顺磁质分子结构上的特点:每个顺磁质分子具有固有分子… 相似文献
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1.问题的提出在普通物理的教学中,磁介质的磁化是比较重要的一部分内容。其中弱磁质的磁化现象比较抽象,初学者难于理解。由于弱磁质的磁化现象很微弱,比铁磁质要弱上几百~几千倍,故在一般的磁场中无法直接观察到。可是如果能把磁场强度提高几百~几千倍,此现象就能象铁磁质磁化那样易于观测了。笔者设计了一种简易的演示装置,利用 相似文献
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首先叙述了由单个轴向磁化环所产生的磁场,并就两个永磁环所产生的纵向磁场进行了分析.对于两个沿同一方向磁化的永磁体环,沿磁环中心线将会产生一个强度较为均匀的轴向磁场.如果两者的磁化方向相反,则在两磁铁间的区域将产生一个纵向的梯度磁场,其磁场强度介于-B0到+B0之间.设计制造了一个高梯度的轴向磁场,其磁场梯度为47.2Tm,测量结果与计算结果非常一致.文中还讨论了产生变梯度磁场的方法.由于永磁环所产生的磁场和螺线管的磁场较为相似,磁铁外部空间将有较大的漏场,最后还讨论了屏蔽漏场的问题. 相似文献
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Hydromagnetic turbulent shear flow of viscous, incompressible, electrically conducting fluid between two infinite uniformly porous moving parallel planes in the presence of axial and transverse magnetic field has been studied by the semi-empirical method. The expressions for the mean distributions for velocity and magnetic field for turbulent shear flow have been obtained for both the cases. As particular cases, the results have been obtained if the planes are fixed. The solutions obtained when the magnetic field is axial have been shown graphically for turbulent and laminar flows. 相似文献
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G.-F. Zhang S.-S. Li 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,37(1):123-127
The thermal entanglement in a two-spin-qutrit system with two
spins coupled by exchange interaction under a magnetic field in an
arbitrary direction is investigated. Negativity, the measurement
of entanglement, is calculated. We find that for any temperature
the evolvement of negativity is symmetric with respect to magnetic
field. The behavior of negativity is presented for four different
cases. The results show that for different temperature, different
magnetic field give maximum entanglement. Both the parallel and
antiparallel magnetic field cases are investigated qualitatively
(not quantitatively) in detail, we find that the entanglement may
be enhanced under an antiparallel magnetic field. 相似文献
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Viscous conducting flows parallel to a fixed plate are studied. In contrast with the Hartmann setting, the problem is not linearized near a fixed transverse magnetic field, although the field tends to be transversal far from the wall. While general solutions may be formally obtained for all cases, their behavior is far more clear when the magnetic Prandtl number equals one. We consider two different instances: a fixed magnetic field at the wall, or an insulating sheet. The evolution of the flow and the magnetic field both near the plate and far from it are detailed, analyzing the possibility of reverse flow and instability of the solutions. 相似文献
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超短超强激光因其极端的物理参数范围以及可用于研究相对论等离子体等特征,成为当前激光驱动磁重联物理的研究热点.通常采用两路激光与平面靶相互作用实现激光驱动磁重联,然而在实验诊断中,由于激光等离子体自身的复杂性导致很难辨别磁重联的物理特征.本文对两路短脉冲激光驱动平面靶磁重联进行了数值模拟,重点分析了靶后电势分布特征和磁重联之间的关系.模拟结果显示,靶后电势分布可以直接影响被加速离子在探测面上的空间分布,因此可用来直接诊断短脉冲激光驱动磁重联实验. 相似文献
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E. A. Kochetov H. Leschke M. A. Smondyrev 《Zeitschrift für Physik B Condensed Matter》1992,89(2):177-186
The problem of a Pekar-Fröhlich polaron in a magnetic field is considered for weak electron-phonon interaction. A diagrammatic technique for zero temperature is developed. Previously obtained results for two dimensions are reproduced. For three dimensions the polaron ground-state energy and the longitudinal effective mass are derived in the first orders of the electron-phonon coupling constant for non-zero values of a magnetic field. In a strong magnetic field the bulk polaron is shown to be equivalent to a one-dimensional polaron with a renormalized electron-phonon coupling constant. This leads to exact results in the strong-coupling limit. 相似文献
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A theoretical investigation is conducted on the dynamic and energetic characteristics of a multi-stable bimorph cantilever energy harvester that uses magnetic attraction effect. The multi-stable energy harvester under study is composed of a bimorph cantilever beam with soft magnetic tip and two externally fixed permanent magnets that are arranged in series. With this configuration, the magnetic force and the moment that are exerted on the cantilever tip tend to be highly dependent on the magnetic field induced by the external magnets. Such an energy harvester can possess multi-stable potential functions, ranging from mono-stable to penta-stable. The mechanism that governs the formation of this multi-stability is thoroughly identified and examined thorough a bifurcation analysis performed on the system?s equilibrium solutions. From this analysis, it is found that the transitions between these multi-stable states occur through very complicated bifurcation scenarios that include degenerate pitchfork bifurcations and mergers of pitchfork bifurcations or saddle-node bifurcations. Bifurcation set diagram is obtained, which is composed of five separate parametric regions, from mono- to penta-stability. The resulting stability map satisfactorily describes the multi-stable characteristics of the present energy harvester. In addition, the dynamic and energetic characteristics of the present multi-stable energy harvester are more thoroughly examined using its potential energy diagrams and a series of numerical simulations, and the obtained results are compared with those for the equivalent bi-stable cases. 相似文献
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The Reflection of Magneto-Thermoelastic $P$ and $SV$ Waves at a Solid Half Space Using Dual-Phase-Lag Model 下载免费PDF全文
Ahmed E. Abouelregal 《advances in applied mathematics and mechanics.》2011,3(6):745-758
The dual-phase-lag heat transfer model is employed to study the reflection
phenomena of $P$ and $SV$ waves from a surface of a semi-infinite
magneto-thermoelastic solid. The ratios of reflection coefficients to that
of incident coefficients are obtained for $P$- and $SV$-wave cases. The
results for partition of the energy for various values of the angle of
incidence are computed numerically under the stress-free and rigidly fixed
thermally insulated boundaries. The reflection coefficients are depending on
the angle of incidence, magnetic field, phase lags and other material
constants. Results show that the sum of energy ratios is unity at the
interface. The results are discussed and depicted graphically. 相似文献