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arXiv 1001.1328cond-mat.mtrl-scicond-mat.other
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具有面内和垂直磁化方向的图案化磁性纳米结构的自组织合成

Self-organized synthesis of patterned magnetic nanostructures with in-plane and perpendicular to the plane magnetization

H. Krishna, A. K. Gangopadhyay, J. Strader, R. Kalyanaraman

摘要:

利用纳秒激光诱导自组织技术,在SiO_{ \text{2} }衬底上制备了Co、Ni和Fe_{ \text{50} } Co_{ \text{50} }铁磁纳米粒子阵列。通过电子显微镜、原子力显微镜和磁力显微镜技术的结合,研究了纳米颗粒阵列的形态、纳米结构和磁性行为。透射电子显微镜的调查显示,一个颗粒状的多晶纳米结构,与纳米粒子内的颗粒数量增加,其直径。磁力测量表明,Co和Ni纳米粒子的磁化方向主要为面外磁化,而Fe_{ \text{50} }Co_{ \text{50} }合金的磁化方向主要为面内磁化。这种行为上的差异是由于磁致伸缩能量对磁化的主导影响,作为快速激光处理后的残余热应变的结果。由于多晶Co和Ni的磁致伸缩系数为负,而Fe_{ \text{50} }Co_{ \text{50} }的磁致伸缩系数为正,拉伸残余应变迫使负磁致伸缩材料的磁化方向在面外,而正磁致伸缩材料的磁化方向在面内。这证明了一种具有成本效益的非外延技术,用于制造具有定制磁化方向的磁性纳米颗粒的图案化阵列。

英文摘要:

Patterned arrays of ferromagnetic nanoparticles of Co, Ni, and Fe_{\text{50}} Co_{\text{50}} have been synthesized from their ultrathin metal films on SiO_{\text{2}} substrate by nanosecond laser-induced self-organization. The morphology, nanostructure, and magnetic behavior of the nanoparticle arrays were investigated by a combination of electron, atomic force, and magnetic force microscopy techniques. Transmission electron microscopy investigations revealed a granular polycrystalline nanostructure, with the number of grains inside the nanoparticle increasing with their diameter. Magnetic force measurements showed that the magnetization direction of the Co and Ni nanoparticles was predominantly out-of-plane while those for the Fe_{\text{50}}Co_{\text{50}} alloy was in the plane of the substrate. This difference in behavior is due to the dominating influence of magnetostrictive energy on the magnetization as a result of residual thermal strain following fast laser processing. Since the magnetostriction coefficient is negative for polycrystalline Co and Ni, and positive for Fe_{\text{50}}Co_{\text{50}}, the tensile residual strain forces the magnetization direction of the negative magnetostriction materials out-of-plane and the positive magnetostriction materials in-plane. This demonstrates a cost-effective non-epitaxial technique for the fabrication of patterned arrays of magnetic nanoparticles with tailored magnetization orientations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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