Researchers at the National Institute of Standards and Technology (NIST) have developed a new microscope able to view and measure an important but elusive property of the nanoscale magnets used in an advanced, experimental form of digital memory. The new instrument already has demonstrated its utility with initial results that suggest how to limit power consumption in future computer memories.
NIST’s heterodyne magneto-optic microwave microscope, or H-MOMM, can measure collective dynamics of the electrons’ spins—the basic phenomenon behind magnetism—in individual magnets as small as 100 nanometers in diameter. Nanomagnets are central components of low-power, high-speed “spintronic” computer memory, which might soon replace conventional random-access memory. Spintronics relies on electrons behaving like bar magnets, pointing in different directions to manipulate and store data, whereas conventional electronics rely on charge.
项目负责人汤姆·席尔瓦（Tom Silva）说：“测量技术完全是新颖的，它启用的能力是前所未有的，科学的结果是开创性的。”
As described in a new paper,* NIST researchers used the H-MOMM to quantify, for the first time, the spin relaxation process—or damping—in individual nanomagnets. Spin relaxation is related to how much energy is required to switch a unit of spintronic memory between a 0 and a 1 (the bits used to represent data).
实验性旋转系统中使用的纳米磁铁太大，无法将其秘密用于常规的原子物理工具，但对于用于散装材料的技术而言太小了。到目前为止，研究人员一直被迫测量纳米磁体组的平均阻尼。新的显微镜使NIST的研究人员能够详细研究由蓝宝石碱基上的镍铁合金制成的单个磁铁中的自旋激发的起伏。
The H-MOMM combines optical and microwave techniques. Two green laser beams are merged to generate microwaves, which excite “spin waves”—magnetic oscillations that vary with position across an individual nanomagnet, like waves in a bathtub. Polarized light from one laser is used to analyze the excitation pattern. By measuring excitation as a function of magnetic field and microwave frequency, researchers can deduce the damping of various spin waves in each nanomagnet.
磁阻尼的测量和控制对于旋转型旋转至关重要，因为阻尼越小，存储一些数据所需的能量越少，并且设备所需的功率越少。NIST研究表明，设计自旋设备具有均匀的自旋波，可以大大减少写入所需的能量。
The new microscope is one outcome of an ongoing NIST effort to develop methods for measuring defects in magnetic nanostructures. At extremely small scales, defects dominate and can disrupt magnetic device behavior, resulting in errors in reading and writing information.
For more information visitwww.nist.gov.
Filed Under:Rapid prototyping
