共查询到16条相似文献,搜索用时 140 毫秒
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实验研究了石榴石磁泡薄膜中不同脉冲宽度下产生的硬磁畴的动态特性.结果表明:由零偏场下产生的枝状畴收缩而成的哑铃畴均逆时针转动,与产生枝状畴时所用的脉冲偏场的脉冲宽度无关.而固定直流偏场下由软畴段硬化而成的哑铃畴的转动状态,则与所用的硬化脉冲偏场的脉冲宽度有关.低脉冲宽度下硬化成的哑铃畴均逆时针转动,随硬化脉冲宽度的升高,出现混合转动向顺时针转动的过渡.由此揭示了直流偏场和脉冲偏场在石榴石磁泡薄膜中形成正、负垂直布洛赫线的作用.
关键词:
磁畴
磁泡
垂直布洛赫线 相似文献
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V. A. Bokov V. V. Volkov N. L. Petrichenko Z. Frait 《Physics of the Solid State》2000,42(12):2250-2253
A study of the domain-wall motion in single-crystal garnet films of the YBiFeGa system with a perpendicular magnetic anisotropy, activated by a constant in-plane bias field H p parallel to the wall plane and a pulsed drive field H g of an amplitude corresponding to the nonlinear region of the domain-wall velocity vs. the H g relation is reported. The earlier data suggesting the existence of an initial phase of motion, where the wall is accelerated to a high instantaneous velocity, have been confirmed. The wall behavior in the initial phase has been shown to be affected by the field H p and the drive-field pulse rise time. A possible mechanism of the wall structure transformation after the application of the H g pulse is considered. It has been established that the dependence of the wall velocity on H p in the saturation region disagrees with theory. 相似文献
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E. I. Il’yashenko O. S. Kolotov A. V. Matyunin O. A. Mironets 《Physics of the Solid State》2006,48(2):297-302
The process of pulsed 90° magnetization of ferrite-garnet films was studied. These films, in addition to easy-plane anisotropy, have biaxial anisotropy in the film plane with an effective field H K2 ? 40–55 Oe. the pulsed magnetization curve contains two portions separated by a kink observed at a field pulse amplitude H p=H p * ? 16–18 Oe. An analysis of the magnetization signals showed that the restoring torque, which is mainly caused by biaxial-anisotropy forces, is overcome in fields H p ≥ H p * and that magnetization rotation occurs. In fields H p < H p * , the magnetization vector rotates at the initial stage only and the angle of rotation ?in is less than 25°–26°. The field H p * and angle ?in are calculated. The results of the calculations are confirmed by experimental data. In fields H p > H p * , the process of magnetization is accompanied by oscillations of the magnetization vector. In contrast to free magnetization oscillations, these oscillations are nonlinear and the frequency of the first harmonic (≈5 × 108 Hz) is much lower than that for free oscillations, (7–12) × 108 Hz. Oscillations are excited at a pulse rise time of ≈6 ns. 相似文献
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V. S. Teslenko A. P. Drozhzhin R. N. Medvedev I. S. Batraev 《Thermophysics and Aeromechanics》2014,21(4):479-488
A new pulsed-cyclic method of in-water gas combustion was developed with separate feed of fuel gas and oxygen with the focus on development of new technologies for heat generators and submerged propellers. The results of calorimetric and hydrodynamic measurements are presented. In-water combustion of acetylene, hydrogen, and propane was tested with the operation frequency of 2–2.5 Hz and with a linear injector. The combustion dynamics of combustion of stoichiometric mixture with propane (C3H8+5O2) was studied for a bubble near a solid wall; the produced gas bubble continues expansion and oscillations (for the case of linear and annular bubbles). It was demonstrated that gas combustion in annular bubbles produces two same-magnitude pulses of force acting on the wall. The first pulse is produced due to expansion of combustion products, and the second pulse is produced due to axial cumulative processes after bubble collapse. This process shapes an annular vortex which facilitates high-speed convective processes between combustion products and liquid; and this convection produces small-size bubbles. 相似文献
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We report our micromagnetic simulations based on Landau-Lifshitz-Gilbert (LLG) equation for CoFeB nanowire which was exposed by sub-nanosecond magnetic pulse with varied pulse width between 100 and 1000 ps. It is found that the Walker Breakdown field (HWB) shifted as the field pulse duration decreased and reached at the highest value in case of 100 ps pulse width, then decreased steeply with respect to the pulse width up to 400 ps. HWB values are not significantly dependent for pulses longer than 500 ps. It is observed that, below the HWB, the exchange energy is larger than the demagnetization energy in the wider nanowire. By energy density analysis, it is understood that the increase of HWB values in the cases of narrower pulse width was to compensate the energy needed to move the DW. 相似文献
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J. Belana P. Colomer M. Pujal S. Montserrat 《Journal of Macromolecular Science: Physics》2013,52(4-6):467-481
The relation between the temperature Tα of the dipolar relaxation, obtained by the technique of thermally stimulated currents (TSC) and the glass transition temperature Tg has been studied in amorphous poly(ethylene terephthalate) samples. The temperature Tα depends fundamentally on the polarization temperature Tp, the polarization time tp, and the heating rate v. For each heating rate a maximum Tα, TM, was obtained for an optimum polarization temperature Tpo. The value of Tpo is 70°C, independent of the heating rate, and very close to the glass transition temperature obtained by differential scanning calorimetry (69°C). The resulting value for TM coincides with Tpo in the limits of null heating rate and null isothermal polarization time, and, consequently, TM gives the value of the glass transition temperature for each heating rate as a function of the isothermal dipolar contribution on polarizing at the temperature Tpo. 相似文献