CAREER: Probing and Controlling the Magnetic Properties of Spinel Ferrite Nanoparticles through Crystal Chemistry

这个项目的目标是设计和制备具有特定磁性的纳米颗粒，并在原子水平上了解决定磁性纳米颗粒潜在新特性的因素，特别是超顺磁性。为了实现这一理解，将采用跨学科的方法，结合化学合成、高分辨率电子显微镜表征、中子衍射、穆斯堡尔光谱和磁测量，系统地阐明磁性、化学成分和结构之间的关系。对尖晶石铁氧体纳米颗粒进行了系统的研究。研究了不同尺寸纳米粒子的晶体化学性质，如阳离子分布和氧化态，并系统地研究了其与居里温度、磁化滞后、超顺磁弛豫等磁性能的关系。使用具有明确晶体化学定义的纳米颗粒，将明确确定颗粒大小和磁性之间的关系。SQUID磁强计、中子衍射、电子能量损失谱和穆斯堡尔谱将用于这些晶体化学和磁性能的研究。我们将系统地研究磁耦合对尖晶石铁氧体纳米粒子超顺磁性能的影响。成为一名优秀的教师是学术生涯成功的重要组成部分。这包括通过参与教师教学改进计划和课堂教学创新活动，大力提高教学技能。建议的研究项目将与教学活动很好地结合，包括为本科教学实验室开发实验和广泛地训练学生的研究能力。这些建议的研究将对磁性纳米级材料的应用产生重大影响，如超顺磁性纳米颗粒。了解和控制纳米颗粒的超顺磁性能在信息技术领域具有重要意义，因为它关系到用于高密度信息存储的磁性数据位的热稳定性。它在生物医学应用中也至关重要，例如磁共振成像（MRI）的造影剂和磁引导药物递送的磁性载体。

9875892 Zhang This goal of this project is to design and prepare nanol articles with specific magnetic properties, and to understand at the atomic level the factors determining potentially novel properties of magnetic nanoparticles, especially superparamagnetic properties. To achieve this understanding, an interdisciplinary approach that combines chemical synthesis, high-resolution electron microscopy characterization, neutron diffraction, Mossbauer spectroscopy and magnetic measurements will be used to systematically elucidate the relationships between magnetic properties, chemical composition and structure. Nanoparticles of spinel ferrites will be systematically studied. The crystal chemistry, such as the cation distribution and the oxidation states nanoparticles of various sizes will be studied, and the relationship to magnetic properties, such as the Curie temperature, magnetization hysteresis, superparamagnetic relaxation will be systematically investigated. Using nanoparticles with well-defined crystal chemistry, relationships between particle size and magnetic properties will be unambiguously determined. SQUID magnetometry, neutron diffraction, electron energy loss spectroscopy, and Mossbauer spectroscopy will be used in these studies of crystal chemistry and magnetic properties. We will systematically study the effect of magnetic couplings on the superparamagnetic properties of these spinel ferrite nanoparticles. Being an excellent teacher is a major part of a successful career in academia. This includes vigorously enhancing teaching skills through participating in faculty teaching enhancement programs and in activities for the innovation of classroom teaching. The proposed research project will be well integrated with teaching activities including developing experiments for the undergraduate teaching laboratory and broadly training students in research.%%%These proposed studies will have a significant impact on applications of magnetic nano-scale materials such as superparamagnetic nanoparticles. Understanding and controlling the superparamagnetic properties of nanoparticles is of great interest in information technology as it relates to the thermal stability of magnetic data bits for high density information storage. It is also crucial in biomedical applications such as contrast agents for magnetic resonance imaging (MRI) and magnetic carriers for magnetically guided drug delivery.