基于钴和坡莫合金纳磁体的全自旋逻辑器件开关特性研究

基于纳磁体动力学和自旋传输机理, 建立了全自旋逻辑(ASL)器件的自旋传输-磁动力学模型. 基于该模型分别研究了钴纳磁体构成的全自旋逻辑(CoASL)器件和坡莫合金纳磁体构成的全自旋逻辑(PyASL)器件在不同沟道长度和电源电压下的开关特性. 结果显示PyASL器件在开关延迟时间和功耗上要小于CoASL器件, 且能可靠工作的最大沟道长度要大于CoASL器件. 另外, 两种ASL器件的开关延迟时间可通过减小沟道长度或增加电源电压来减小; 而功耗可通过减小沟道长度或电源电压来减小. 同时, 减小沟道长度能有效抑制热噪声对开关延迟时间和功耗的影响, 但增大电源电压只能抑制热噪声对开关延迟时间的影响. 上述研究结果将为优化ASL器件磁性材料和器件结构提供重要的参数选择依据.

Switching characteristics of all spin logic devices based on Co and Permalloy nanomagnet

The need for low-power alternatives to digital electronic circuits has aroused the increasing interest in spintronic devices for their potentials to overcome the power and performance limitations of (CMOS). In particular, all spin logic (ASL) technology, which stores information using the magnetization direction of the nano-magnet and communicates using spin current, is generally thought to be a good post-CMOS candidate for possessing capabilities such as nonvolatiliy, high density, low energy dissipation. In this paper, based on nano-magnetic dynamics described by Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation and transport physics of spin injection and spin diffusion, a coupled spin-transport/magneto-dynamics model for ASL is established. Under different channel lengths and applied voltages, the switching characteristics of ASL device comprised of Co and Permalloy (Py) nano-magnets are analyzed by using the coupled spin-transport/magneto-dynamics model. The results indicate that the switch delay, energy dissipation and thermal noise effect of PyASL are lower than those of CoASL. The main reason is that the saturation magnetization of Py is less than that of Co. Under the same applied voltage, the maximal channel length of PyASL is longer than that of CoASL when ASL device can switch accurately. Moreover, the two ASL devices' switching delay can be reduced by reducing channel length or increasing applied voltage, and the energy dissipation can be reduced by reducing channel length or applied voltage, whereas there are no optimized applied voltages to minimize the energy-delay product. In addition, the influences of thermal noise on switching delay and energy dissipation can be improved by lowering channel length, but increasing applied voltage can only improve the influence of thermal noise on switching delay. The above-mentioned conclusions will supply essential guidelines for optimizing the ASL devices' materials and configuration.