High-speed dynamics, damping, and relaxation times in submicrometer spin-valve devices
High-speed dynamics, damping, and relaxation times in submicrometer spin-valve devices
复制标题
DOI：
10.1063/1.372934
复制
发表时间：
2000-05-01
影响因子：
3.2
通讯作者：
Donahue, MJ
中科院分区：
文献类型：
--
作者：
Russek, SE;Kaka, S;Donahue, MJ
测量了线宽为0.8 μ m的自旋阀器件在160 ps磁脉冲激励下的动态响应。这些器件显示出2- 4GHz的谐振频率，这决定了它们的工作频率的上限。可以用Landau-Lifshitz模型拟合动态响应，以提取有效的均匀模式阻尼常数alpha（um）。α（μ m）的测量值在0.04和0.01之间，这取决于纵向偏置场的大小。从具有大纵向偏置场的动态响应中提取用于微磁建模的适当阻尼系数α（mm）。这个值被用来模拟0.1 μ mx1.0 μ m磁阻随机存取存储器单元的开关。微磁模型包括预期在真实的器件中发现的形状无序。模拟显示，虽然磁化迅速反转（< 0.5 ns），但从磁系统中移除能量需要几纳秒。开关能量存储在短波长的磁波动，可以显着影响再反转过程后1-2 ns的第一个反转。【S0021-8979（00）70908-X】。
The dynamical response of spin-valve devices with linewidths of 0.8 mu m has been measured after excitation with 160 ps magnetic impulses. The devices show resonant frequencies of 2-4 GHz which determine the upper limit of their operation frequency. The dynamical response can be fit with Landau-Lifshitz models to extract an effective uniform-mode damping constant, alpha(um). The measured values of alpha(um) were between 0.04 and 0.01 depending on the magnitude of the longitudinal bias field. The appropriate damping coefficient for use in micromagnetic modeling, alpha(mm), was extracted from the dynamical response with large longitudinal bias field. This value was used to model the switching of a 0.1 mu mx1.0 mu m magnetoresistive random access memory cell. The micromagnetic model included shape disorder that is expected to be found in real devices. The simulations showed that, while the magnetization reverses rapidly (< 0.5 ns), it took several nanoseconds for the energy to be removed from the magnetic system. The switching energy was stored in short wavelength magnetic fluctuations that could dramatically affect the re-reversal process 1-2 ns after the first reversal. [S0021-8979(00)70908-X].