共查询到20条相似文献,搜索用时 15 毫秒
1.
S.H. Liu 《Journal of magnetism and magnetic materials》1979,12(3):262-276
We have studied the propagation of spin waves in a number of static non-periodic magnetic structures. We have established that (1) a ferromagnetic spin wave can ride over a domain wall with little reflection if its wavelength is less than twice the thickness of the wall; (2) in a ferromagnet with a set of parallel but irregularly spaced domain walls the spin wave linewidth is determined by the product of the scattering strength of the walls and the degree of randomness of the wall spacings; and (3) spin waves of rather narrow linewidths can exist in continuously varying irregular spin structures. 相似文献
2.
A solution of the problem of parametric interaction between a plane monochromatic shear wave and a uniformly moving 180°-domain wall of a garnet-ferrite crystal is obtained in the exchangeless magnetostatic approximation by using the perturbation method under the conditions of a nonlinear response of the spin subsystem. It is shown that in a ferromagnetic resonance with magnetostatic oscillation of stray fields, the nonlinearity of the spin subsystem leads to the excitation of shear waves of triple frequency, which may have amplitudes comparable with that of the incident wave for oscillations doubly localized by a domain wall. 相似文献
3.
We investigate the spin wave spectra associated to a vortex domain wall confined within a ferromagnetic nanotube. Basing our study upon a simple model for the energy functional we obtain the dispersion relation, the density of states and dissipation induced life-times of the spin wave excitations in presence of a magnetic domain wall. Our aim is to capture the basics spin wave physics behind the geometrical confinement of nobel magnetic textures. 相似文献
4.
孙东升 《原子与分子物理学报》2003,20(3):351-356
研究获得了相对论性无自旋氢原子散射态的精确解,给出了精确的相移表达式和按"k/2π标度"归一化的散射态的径向波函数,讨论了散射振幅的解析性质 . 相似文献
5.
The boundary-value problem of the interaction of a plane monochromatic shear wave with a moving Bloch wall in an iron garnet crystal is solved in the framework of the nonexchange magnetostatic approximation on the basis of the method of phase invariants for wave problems with moving boundaries. For a shear wave incident on the domain wall, the possibility of the reflectionless birefringence is demonstrated. Numerical results illustrating the resonance properties of the magnetic subsystem are presented. It is established that, at the upper bound of the reflectionless birefringence range, the interaction of the shear wave with the domain wall manifests itself as a degenerate resonance with the solution in the form of two combined antiphase, collinearly propagating shear waves of infinitely large amplitudes, which form a zero resulting field. 相似文献
6.
An exact solution of the equation for spin waves propagating along the normal to the domain wall is derived for a ferromagnet with a 180° domain wall moving at constant speed, and the radiation of spin waves in rf fields is investigated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 66–69, April, 1979. 相似文献
7.
The spin-wave transportation through a transverse magnetic domain wall (DW) in a magnetic nanowire is studied. It is found that the spin wave passes through a DW without reflection. A magnon, the quantum of the spin wave, carries opposite spins on the two sides of the DW. As a result, there is a spin angular momentum transfer from the propagating magnons to the DW. This magnonic spin-transfer torque can efficiently drive a DW to propagate in the opposite direction to that of the spin wave. 相似文献
8.
The mode spectrum of electroacoustic boundary waves guided by a strip domain uniformly moving in a 4-mm ferroelectric is considered
in the quasi-static approximation. The motion of the strip domain is found to cause the wave vector of the electroacoustic
wave to be noncollinear with the guiding boundaries. The frequency dependences of the phase velocity are presented for the
symmetric and antisymmetric modes of the electroacoustic wave. These dependences are compared in the reference system fixed
to the strip domain and in the laboratory reference system. It is shown that, at low and moderate frequencies, the symmetric
mode of the electroacoustic wave is more efficiently localized by a moving strip domain than by a single domain wall. 相似文献
9.
Vilkov E. A. Shavrov V. G. Shevyakhov N. S. 《Radiophysics and Quantum Electronics》2001,44(8):656-667
Using Galileo's transformation for moving to the rest frame of the Bloch wall in the exchange-free magnetostatic approximation, we obtain the dispersion relation for a shear surface wave guided by a moving 180-degree domain boundary of a ferromagnetic crystal. It is found that the motion of the domain boundary has the orienting action on the wave normal of the shear surface wave and significantly changes the spectrum of forward-propagating waves in the frequency band below the scattered-field ferromagnetic resonance. 相似文献
10.
We consider a simple exactly solvable model of an order-disorder transition: noninteracting interfaces moving with constant speed in one dimension. We obtain a linear increase with time of the average domain size and a weak oscillatory behavior of the scattering structure function. 相似文献
11.
R.L. Leheny Y.S. Lee G. Shirane R.J. Birgeneau 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(3):287-290
Inelastic neutron scattering with high wave-vector resolution has characterized the propagation of transverse spin wave modes
near the antiferromagnetic zone center in the metastable domain state of a random field Ising magnet. A well-defined, long
wavelength excitation is observed despite the absence of long-range magnetic order. Direct comparisons with the spin wave
dispersion in the long-range ordered antiferromagnetic state reveal no measurable effects from the domain structure. This
result recalls analogous behavior in thermally disordered anisotropic spin chains but contrasts sharply with that of the phonon
modes in relaxor ferroelectrics.
Received 2 November 2002 / Received in final form 4 February 2003 Published online 11 April 2003
RID="a"
ID="a"leheny@pha.jhu.edu 相似文献
12.
13.
The dependence of the domain wall velocity V on the acting magnetic field H is investigated for bismuth-containing single-crystal garnet ferrite films with orthorhombic magnetic anisotropy. It is shown that this dependence includes both the initial linear portion and a saturation portion and exhibits a complex behavior. This behavior is explained within the model of domain wall motion with spin wave radiation. 相似文献
14.
Reflection of solitary flexural waves propagating in a supersonic domain wall of yttrium orthoferrite from the domain wall part moving with the transverse-sound velocity is observed experimentally. This observation confirms that such a reflection of a solitary flexural wave leads to a change in the sign of the topological charge of the antiferromagnetic vortex accompanied by this wave, which proves a direct relationship between these two objects. 相似文献
15.
E. A. Vilkov 《Acoustical Physics》2005,51(5):524-532
The boundary-value problem of the magnetoelastic wave interaction with a moving domain wall in a ferromagnetic crystal is solved in the nonexchange magnetostatic approximation with allowance for the external magnetic field. It is shown that the difference introduced by magnetic field between the ferromagnetic resonance frequencies of the domains does not cause any noticeably departure of the refraction characteristics of reflected and transmitted waves from those observed at zero frequency mismatch. By contrast, the magnitudes of the transmission and reflection coefficients strongly depend on the external magnetic field and on the mobility of the domain wall. The dependence of the magnitude of the reflection coefficient on the external magnetic field at a fixed angle of shear wave incidence is found to possess two ferromagnetic resonance peaks. The positions and heights of the peaks may vary depending on the mobility of the domain wall. 相似文献
16.
Pumping of charge current by spin dynamics in the presence of the Rashba spin-orbit interaction is theoretically studied. Considering a disordered electron, the exchange coupling and spin-orbit interactions are treated perturbatively. It is found that the dominant current induced by spin dynamics is interpreted as a consequence of the conversion from spin current via the inverse spin Hall effect. We also find that the current has an additional component from a fictitious conservative field. The results are applied to the case of a moving domain wall. 相似文献
17.
Danneau R Warin P Attané JP Petej I Beigné C Fermon C Klein O Marty A Ott F Samson Y Viret M 《Physical review letters》2002,88(15):157201
The resistance generated by individual domain walls is measured in a FePd nanostructure. Combining transport and magnetic imaging measurements, the intrinsic domain wall resistance is quantified. It is found positive and of a magnitude consistent with that predicted by models based on spin scattering effects within the walls. This magnetoresistance at a nanometer scale allows a direct counting of the number of walls inside the nanostructure. The effect is then used to measure changes in the magnetic configuration of submicron stripes under application of a magnetic field. 相似文献
18.
The resistivity due to the domain wall in the presence of impurities in a ferromagnetic metallic wire is calculated based on the linear response theory. Assuming the local spin distribution to be spin-spiral the modification of the band structure has been obtained exactly. With this modified band structure we calculate the conductivity of the system as a function of electronic filling and show that the domain-wall contribution to the resistance can be positive or negative depending on the dimensionality, the position of the Fermi energy on the band structure and the strength of the electron local spin interaction of the system. 相似文献
19.
We describe here an example of a dynamical system which preserves the distance between constituent particles. Namely, we consider
the one-dimensional finite magnetic Heisenberg ring of an even numberN of nodes with the spin 1/2, solved exactly by the well-known Bethe ansatz (XXX model). It is described in terms of a number
of spin deviations from the ferromagnetic saturation state (a system of Bethe pseudoparticles) which undergo processes of
mutual solitonic scattering when moving on the ring. We point out that, when restricting to (i) the subspace of quantum states
with two spin deviations and (ii) to the boundary of the Brillouin zone, Bethe pseudoparticles perfectly avoid any mutual
scattering. Therefore, each state with a fixed distance between pseudoparticles (the so called basis of wavelets) is already
an eigenstate of the initial Heisenberg Hamiltonian.
Presented by T. Lulek at the DI-CRM Workshop held in Prague, 18–21 June 2000.
The authors are very much indebted to Professors J. Patera and J. Tolar for their invitation to DI-CRM Workshop on Mathematical
Physics, and for their kind hospitality during the Workshop. 相似文献
20.
P. D. Sacramento M. A.N. Araújo 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,76(2):251-259
We calculate the spin density, spin currents and spin torque due to a spin polarized current on a magnetic domain wall juxtaposed
to or inserted in a conventional superconductor. The superconductor is part of a heterostructure of the type NSN or FSF. In
general, the spin torque exerted on the domain wall is weaker with respect to a normal metal. However, there are regimes where
the torque is enhanced with respect to the normal metal. In these regimes the motion of the domain wall is therefore more
efficient. A notable case is the passing of an unpolarized current which leads to a finite torque in the case of the superconductor. 相似文献