共查询到20条相似文献,搜索用时 31 毫秒
1.
A. Vernes L. Szunyogh L. Udvardi P. Weinberger 《Journal of magnetism and magnetic materials》2002,240(1-3):215-216
The complex optical conductivity tensor is calculated for the Co | Pt multilayer systems by applying a contour integration technique within the framework of the spin-polarized relativistic screened Korringa–Kohn–Rostoker method. It is shown that the optical conductivity of the Co | Pt multilayer systems is dominated by contributions arising from the Pt cap and/or substrate layers. 相似文献
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This paper obtains the 1-soliton solution of the nonlinear Schrödinger’s equation in a Kerr law media. The technique that is used to carry out the integration of this equation is the Lie symmetry analysis. 相似文献
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Wilhelm F Poulopoulos P Ceballos G Wende H Baberschke K Srivastava P Benea D Ebert H Angelakeris M Flevaris NK Niarchos D Rogalev A Brookes NB 《Physical review letters》2000,85(2):413-416
The magnetic moments in Ni/Pt multilayers are thoroughly studied by combining experimental and ab initio theoretical techniques. SQUID magnetometry probes the samples' magnetizations. X-ray magnetic circular dichroism separates the contribution of Ni and Pt and provides a layer-resolved magnetic moment profile for the whole system. The results are compared to band-structure calculations. Induced Pt magnetic moments localized mostly at the interface are revealed. No magnetically "dead" Ni layers are found. The magnetization per Ni volume is slightly enhanced compared to bulk NiPt alloys. 相似文献
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The anomalous loops obtained by applying the traditional Kerr loop technique, in which the sample was pumped by continuous pulses using the method of successive increment scanning external magnetic field, contained memory and accumulation effects originating, respectively, from external field history and multiple pulse excitations. To eliminate the memory effect and study the influence of external magnetic field on the anomalous loops, an initializing field scanning approach was used to replace the method of successive increment scanning external field. And to confirm the existence of accumulation effect and study the influence of pump pulses on the anomalous loops, a controllable pump-pulse-number magneto-optical Kerr technique was used to replace continuous pulses pump Kerr technique. In both ways, measured with different pump fluence and different pump pulses, the results showed clearly the dependence of the hot coercivity and the degree of magnetization reversal on the external field, pump pulse numbers and pump fluence. 相似文献
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Lifu Zhang Shuangchun Wen Xiquan Fu Jianqin Deng Jin Zhang Dianyuan Fan 《Optics Communications》2010,283(10):2251-2214
We investigated the spatiotemporal modulation instability (MI) in a medium with a non-instantaneous Kerr response in which the nonlinear contribution to the refractive index is governed by a relaxing Debye type equation. The expression for the MI gain spectrum in non-instantaneous Kerr medium is obtained, which clearly reveals the influence of the finite time of the nonlinear response (relaxation effect) on the spatiotemporal MI. It is shown that, due to the relaxation effect, the spatiotemporal MI can appear for the case of anomalous dispersion and defocusing nonlinearity, while it cannot appear in instantaneous Kerr medium for the same case, and a new MI gain spectrum appears, adding to the conventional MI gain spectrum similar to that in an instantaneous Ker medium. In addition, the bandwidth of MI gain spectrum is extended and the maximum MI gain is reduced with increasing of the relaxation time. Interestingly, spatiotemporal MI can appear for any spatial frequencies in non-instantaneous Kerr medium for any combination of dispersion and nonlinearity. We have performed an experiment of MI in carbon disulfide (CS2), a typical non-instantaneous Kerr medium, which shows quantitative agreement with the theoretical analyses. 相似文献
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Andrea Melloni 《Fiber and Integrated Optics》1999,18(1):1-13
The Kerr and the electrostrictive contributions to the intensity-dependent nonlinear refractive index in optical fibers are discussed on both theoretical and experimental bases. Particular attention is devoted to the electrostrictive contribution that under particular conditions is enhanced by resonances. The resonant behavior of the electrostrictive effect is calculated, measured, and discussed for standard single-mode fibers and dispersion shifted fibers. Experimental results are also reported. Measure ments have been carried out with a simple and effective technique based on the cross-phase modulation effect that also allows one to evaluate the nonlinear refractive index at any bit rate. Electrostriction contributes 20 % to the total nonlinear refractive index but in the resonant regime becomes comparable to the Kerr effect. 相似文献
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Vassilios Yannopapas 《Optics Communications》2010,283(8):1647-1649
It is shown that the Kerr nonlinearity of a two-level atom placed in the vicinity of a two-dimensional array of metal-coated silica nanoparticles can be greatly enhanced due to quenching of both radiative and non-radiative spontaneous-emission paths for frequencies near the surface plasmon resonances. The spontaneous emission rate is calculated by rigorous electrodynamic calculations of the electric-field Green’s tensor. The Kerr susceptibility can be enhanced by two orders of magnitude even for large detunings heralding, this way, the observation of nonlinear phenomena for moderate radiation intensities. 相似文献
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以表面磁光克尔原理为机理,测量薄膜材料的磁性参数,实验上求得了饱和状态下坡莫合金的克尔偏转角,并测出了其磁滞回线. 相似文献
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A novel atom configuration is proposed for a giant Kerr nonlinearity in zero linear and nonlinear probe absorption. It is shown that without coherent control field and just by quantum interference of spontaneous emission, a giant Kerr nonlinearity can be obtained. 相似文献
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CoPt alloy films with good magnetic and mageto-optical properties were prepared on Pt buffer layer or directly on glass subst rate by sputtering a composite target. Their static recording properties were investigated. The results showed that static signals could be easily written into the CoPt alloy films without Pt buffer layers using moderate recording power. The introduction of Pt buffer layer in CoPt alloy films not only led to a smaller Kerr rotation but also greatly increased the recording power. 相似文献
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It is shown in terms of a fully relativistic spin-polarized ab initio-type approach that in Pt/Co/Pt trilayers two types of anisotropic magnetoresistance (AMR) have to be distinguished: an in-plane and an out-of-plane AMR. The obtained results, namely the magnetic field dependence as well as the thickness dependence of both AMR types are in very good agreement with a very recent experimental study, in which the in-plane as well as the out-of-plane AMR was reported for this system. The difference between the two types of AMR is visualized in terms of layer-resolved resistivities. In particular, it is confirmed that the anisotropic interface magnetoresistance (AIMR) introduced in the recent publication mainly originates in the vicinity of the Co/Pt interfaces. 相似文献
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The paper generalizes paraxial complex geometrical optics (PCGO) for Gaussian beam (GB) propagation in nonlinear media of Kerr type. Ordinary differential equations for the beam amplitude and for complex curvature of the wave front are derived, which describe the evolution of axially symmetric GB in a Kerr type nonlinear medium. It is shown that PCGO readily provides the solutions of NLS equation obtained earlier from diffraction theory on the basis of the aberration-free approach. Besides reproducing classical results of self-focusing PCGO readily describes an influence of the initial curvature of the wave front on the beam evolution in a medium of Kerr type including a nonlinear graded-index fiber. The range of applicability of the PCGO theory is discussed as well which is helpful for avoiding nonphysical solutions. 相似文献
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Kerr偶奇相干态及其非经典性 总被引:6,自引:0,他引:6
本文对Ker偶奇相干态及其非经典性质进行了研究。结果表明:Kerr偶相干态可呈现周期性的二阶压缩效应,Kerr奇相干态则不存在这种压缩效应;但两者均可呈现周期性的振幅平方压缩效应,这与通常偶奇相干态的情形有所不同。 相似文献
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We revisit a little known theorem due to Beltrami, through which the integration of the geodesic equations of a curved manifold
is accomplished by a method which, even if inspired by the Hamilton-Jacobi method, is purely geometric. The application of
this theorem to the Schwarzschild and Kerr metrics leads straightforwardly to the general solution of their geodesic equations.
This way of dealing with the problem is, in our opinion, very much in keeping with the geometric spirit of general relativity.
In fact, thanks to this theorem we can integrate the geodesic equations by a geometrical method and then verify that the classical
conservation laws follow from these equations. 相似文献
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Andrey V. Panov 《Annalen der Physik》2020,532(6):1900574
High-index dielectric nanoantennas excited at Mie-type resonances have exhibited enormous enhancement of optical nonlinearity. Such nanostructures have been actively studied by researchers in recent years. Here, a numerical analysis study of the optical Kerr effect of nanocomposites consisting of high refractive index (GaP) spheres at the wavelength of 532 nm is presented. This is done by means of 3D finite-difference time-domain simulations. The effective nonlinear refractive index of 0.8 µm thick nanocomposites and metasurfaces is evaluated. It is shown that the optical Kerr nonlinearity of the nanocomposites rises by orders in proximity to Mie resonances and may exceed the second-order refractive index of the bulk material. It is revealed that the sign of the effective optical Kerr coefficient is inverted near the Mie resonances. This effect may be of interest in developing nonlinear optical metadevices. 相似文献
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X.Y. Chen B. Yang T. Zhu K.H. Wong J.M. Liu Z.G. Liu 《Applied Physics A: Materials Science & Processing》2002,74(4):567-569
(110)-textured MgO films were grown on Si (100) with etching and without etching by pulsed laser deposition. The deposited
MgO films were shown to be droplets-free. The MgO film was used as a buffer layer to further grow Pt film on Si (100). A completely
(110)-oriented Pt film was obtained on such a buffer layer and its surface is very smooth with a roughness of about 7.5 nm
over 5×5 μm. This can be used as a new oriented Pt electrode on silicon for devices.
Received: 23 January 2001 / Accepted: 27 April 2001 / Published online: 27 June 2001 相似文献