Analysis of Spin Polarized Transfer and of Micro-Macro Theories for Polymers and Liquid Crystals

聚合物和液晶的自旋偏振转移和微观宏观理论分析

• 批准号: 0505738
• 负责人: Carlos Garcia-Cervera
• 金额: $ 9.74万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0505738&HistoricalAwards=false
• 关键词: Analysis; Spin; Polarized; Transfer; Micro

The investigator takes up three projects. In the firstproject, the emphasis is the analysis and the design of efficientnumerical methods for the simulation of recent models proposed forthe dynamics of the magnetization coupled to the spin accumulationin multilayers when a current perpendicular to the plane of thelayers is applied. The dynamical equation for the spin is adiffusion equation with discontinuous coefficients, and themagnetization dynamics is described by the Landau-Lifshitzequation from ferromagnetism. In the second project, theinvestigator studies a new model for liquid crystals based onInhomogeneous Density Functional Theory. The model can describethe isotropic, nematic, smectic A, and crystalline phases. Finally, in the third project, the investigator studies theformation of aggregates in polymer mixtures. Ferromagnetic materials are widely used in the magneticrecording industry, which continues to be the dominant technologyfor the storage of digital data. The project addresses some ofthe technological difficulties found in the design of magneticdevices such as magnetic memories (MRAMs). Liquid crystals have awide range of applications. Their optical properties are highlysensitive to electric and magnetic fields, which has made liquidcrystals ideal candidates for optical-switching devices, such asvideo displays and optical memories. They are very sensitive totemperature changes as well, which makes them useful inapplications involving sensors. More generally, polymers appearin most aspects of our life, from the amniotic fluid insidebiological cells, to plastics and shampoos used on a daily basis. Understanding the dynamics of biological membranes and transportthrough them is of fundamental importance in the development ofefficient methods for the delivery of medicines. Understandingthe process of aggregation in polymer mixtures can have asignificant impact in the design of new products. This study ofpolymers and liquid crystals addresses some of these technologicaland biological issues.

研究人员承担了三个项目。 在第一个项目中，重点是分析和设计有效的数值方法，用于模拟最近提出的模型，这些模型是在施加垂直于层平面的电流时与多层中的自旋累积耦合的磁化动力学的动力学。 自旋的动力学方程是具有不连续系数的扩散方程，磁化动力学由铁磁性的Landau-Lifshitz方程描述。 在第二个项目中，研究人员研究了一种基于非均匀密度泛函理论的液晶新模型。 该模型可以描述各向同性相、向列相、近晶A相和结晶相。最后，在第三个项目中，研究人员研究了聚合物混合物中聚集体的形成。 铁磁材料广泛应用于磁记录行业，磁记录行业仍然是数字数据存储的主导技术。 该项目解决了磁存储器（MRAM）等磁性器件设计中发现的一些技术难题。 液晶具有广泛的应用领域。 液晶的光学特性对电场和磁场高度敏感，这使得液晶成为视频显示器和光学存储器等光开关器件的理想选择。 它们对温度变化也非常敏感，这使得它们在涉及传感器的应用中非常有用。 更一般地说，聚合物出现在我们生活的方方面面，从生物细胞内的羊水到日常使用的塑料和洗发水。了解生物膜的动力学及其运输对于开发有效的药物输送方法至关重要。 了解聚合物混合物的聚集过程可以对新产品的设计产生重大影响。 这项对聚合物和液晶的研究解决了其中一些技术和生物问题。