Exploring Phase Separation in Manganite Films

探索锰酸盐薄膜中的相分离

• 批准号: 0512196
• 负责人: Trevor Tyson
• 金额: $ 31.5万
• 依托单位: New Jersey Institute of Technology
• 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: 2005-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0512196&HistoricalAwards=false
• 关键词: Exploring; Phase; Separation; Manganite; Films

Technical Abstract In order to understand the origin and properties of the observed phase coexistence in manganites, this project will measure the magnetic, electronic and structural properties of manganite films on multiple length scales under strain and under pressure. High resolution x-ray diffraction measurements will be applied to determine the lattice parameters of the film components and the substrates. In parallel, the local structure and valence about the transition metal atoms and the oxygen atoms will be determine. In addition to bulk magnetization measurements, detailed magnetic imaging of the surface will be conducted by photoexcitation electron emission microscopy (PEEM) measurements. Patterned films will be examined to explore geometrical effect. The film results will be compared with parallel magnetization and high pressure transport and structural measurements on the corresponding bulk samples. In this way, we will be able to separate extrinsic effects from intrinsic effect as well to explore changes at the surface of manganites in comparison with bulk samples. Graduate and undergraduate students will be involved in all levels of this work including sample preparation, laboratory and synchrotron based measurements, modeling and data analysis. A seven week summer research and teaching program on transition metal oxide preparation and characterization, designed for Newark area high school students will be continued and expanded to include a two-week workshop for high school teachers to enable them to implement components of the program into their laboratory experiments. Non-Technical Abstract Manganite oxides exhibit significant changes in electrical conductivity in response to pressure, magnetic fields, light, and electrical fields. As a result of this sensitivity, these materials show much promise for the development of new magnetic sensors and non-volatile data storage. However, much basic research is needed in order to truly understand the origin of the response to external stimuli and to optimizer them for applications. Understanding phase coexistence is a central part of the required basic research. This project will measure the magnetic, electronic and structural properties of manganite films on multiple length scales under strain and under pressure to fully characterize the response to external perturbations. Synchrotron based x-ray methods will be used to determine the structure, valence and magnetic properties. The results will lead to more detailed models of these materials, and possibly, methods for optimizing them in applications. Graduate and undergraduate students will be involved in all levels of this work including sample preparation, laboratory and synchrotron based measurements, modeling and data analysis. A seven week summer research and teaching program on transition metal oxide preparation and characterization, designed for Newark area high school students will be continued and expanded to include a two-week workshop for high school teachers to enable them to implement components of the program into their laboratory experiments. The program will be integrated into high school science laboratory courses. This will serve to (1) develop scientific literacy and to directly influence students to pursue careers in science, and (2) provide exposure to experimental techniques and methods to high school teachers and high school students and to others who do not have access to modern research facilities.

为了了解锰酸盐中所观察到的相共存的起源和性质，本项目将在应变和压力下测量锰酸盐薄膜在多个长度尺度上的磁性、电子和结构性质。高分辨率x射线衍射测量将用于确定薄膜组件和衬底的晶格参数。同时，还可以确定过渡金属原子和氧原子的局部结构和价态。除了体磁化测量外，表面的详细磁成像将通过光激发电子发射显微镜（PEEM）测量进行。图案化薄膜将被检查以探索几何效应。薄膜的结果将与平行磁化和高压输运以及相应块状样品的结构测量结果进行比较。通过这种方式，我们将能够将外在效应与内在效应分开，并探索与散装样品相比，锰矿石表面的变化。研究生和本科生将参与所有层次的工作，包括样品制备，实验室和同步加速器测量，建模和数据分析。为纽瓦克地区高中生设计的为期七周的过渡金属氧化物制备和表征暑期研究和教学计划将继续进行，并扩大为高中教师提供为期两周的研讨会，使他们能够将计划的组成部分应用到他们的实验室实验中。锰氧化物在压力、磁场、光和电场的作用下，电导率会发生显著变化。由于这种灵敏度，这些材料在开发新的磁传感器和非易失性数据存储方面显示出很大的希望。然而，为了真正了解外部刺激反应的起源并优化它们的应用，还需要进行大量的基础研究。了解相共存是必要基础研究的核心部分。本项目将在应变和压力下测量锰矿薄膜在多个长度尺度上的磁性、电子和结构特性，以充分表征其对外部扰动的响应。基于同步加速器的x射线方法将用于确定其结构、价态和磁性能。这些结果将导致这些材料的更详细的模型，并可能在应用中优化它们的方法。研究生和本科生将参与所有层次的工作，包括样品制备，实验室和同步加速器测量，建模和数据分析。为纽瓦克地区高中生设计的为期七周的过渡金属氧化物制备和表征暑期研究和教学计划将继续进行，并扩大为高中教师提供为期两周的研讨会，使他们能够将计划的组成部分应用到他们的实验室实验中。该计划将被纳入高中科学实验课程。这将有助于(1)培养科学素养，并直接影响学生从事科学事业，(2)为高中教师和高中生以及其他无法接触到现代研究设施的人提供接触实验技术和方法的机会。