NER: Synthesis and Characterization of Self-Assembled Nanoscale Magnetic Particles

该补助金探索了脉冲激光沉积（PLD）辅助自组织生长均匀的磁性纳米颗粒（岛）的理想形状，尺寸和浓度在不同的薄膜基质的发展。磁性纳米颗粒材料将由单一元素（例如Fe、Co、Ni等）和非磁性纳米颗粒材料构成。以及多元素合金（如Fe-Pt、Sm-Fe-Ti等）。基体材料将由氧化铝（如Al 2 O3和SiO2）和氮化物（如TiN、AlN）构成。改变衬底温度、决定到达衬底表面上的吸附原子的数量密度的激光能量密度以及气体环境的压力以控制磁性纳米颗粒的尺寸、形状和体积分数。本项目开发的自组装纳米复合材料将为磁性能测量和分析提供一系列材料。目标是使用先进的显微结构技术，如扫描透射电子显微镜与原子序数对比（STEM-Z）和电子能量损失谱（EELS）用原子大小探针来确定界面的结构以及局部化学和纳米级构件与其周围环境之间的分离和相互作用的影响。拟议活动的更广泛影响将是发展（i）一种新的方法，用于自组装纳米磁性粒子与窄粒度分布，（ii）在纳米尺度上的磁性的基本理解，（iii）从原子分辨率Z-对比度图像的纳米粒子形状的三维重建的新技术，和（iv）研究生和本科生在纳米技术领域的研究和教育计划。

The grant explores development of pulsed laser deposition (PLD) assisted self-organized growth of uniform magnetic nanoparticles (islands) of ideal shape, dimension, and concentration in different thin film matrices. The magnetic nanoparticle materials will be constituted of both single elements (such as Fe, Co, Ni, etc.) and multielemental alloys (such as Fe-Pt, Sm-Fe-Ti, etc.). The matrix materials will be constituted of nonmagnetic oxide (such as Al2O3 and SiO2) and nitride (such as TiN, AlN). The substrate temperature, laser energy density determining the number density of arriving adatoms on substrate surface, and pressure of the gas ambient will be varied to control the size, shape and volume fraction of magnetic nanoparticles. The self-assembled nanocomposites developed in this project will provide a range of materials for magnetic properties measurements and analyses. The goal is to use advanced microstructural techniques such as scanning transmission electron microscopy with atomic number contrast (STEM-Z) and electron energy loss spectroscopy (EELS) with atomic size probe to determine the structures of the interfaces as well as the local chemistries and the effects of segregation and interaction between the nanoscale building blocks and their surroundings.The broader impacts of the proposed activity will be the development of (i) a new method for selfassembly of nanomagnetic particles with narrow particle size distribution, (ii) a fundamental understanding on magnetic properties at the nanoscale, (iii) new techniques for three-dimensional reconstruction of nanoparticle shape from atomic resolution Z-contrast images, and (iv) research and education programs for graduate and undergraduate students in the area of nanotechnology.