Strain Effects in Thin Manganite Films Grown by Laser-MBE

激光 MBE 生长的锰氧化物薄膜的应变效应

• 批准号: 9972973
• 负责人: Qi Li
• 金额: $ 29.88万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9972973&HistoricalAwards=false
• 关键词: Strain; Effects; Thin; Manganite; Films

This project addresses growth of heteroepitaxial manganite thin films on lattice mismatched substrates to provide pseudomorphic films with controlled levels of strain and with controlled morphology to assess the primary influence of strain on colossal mag-netoresistance (CMR ). The film growth studies utilize Laser-MBE, which combines conventional MBE conditions with pulsed-laser deposition. Thrusts of the project are: to grow fully strained manganite thin films with controlled surface mor-phology and low defect concentration using Laser-MBE; to control strain in the films by using different substrates and to fully characterize the strain; and through study of mag-netic and magnetotransport properties to reveal the strain effects on mechanisms of magnetotransport properties, the low field magnetoresistance(MR), and the magnetic and MR anisotropy of the man-ganite materials. These studies are expected to provide new information to better understand the origin of the large low field MR in strained ultrathin manganite films, as well as electron-lattice coupling, and magnetic and MR anisotropy in manganite films. %%%The project addresses basic research issues in a topical area of materials science having high potential technological relevance. The success of this research may lead to advances in the technological development of devices based on magnetoresistance. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***

该项目解决了异质外延锰氧化物薄膜的晶格失配衬底上的生长，以提供具有受控水平的应变和受控形态的赝晶薄膜，以评估应变对巨大磁电阻（CMR）的主要影响。薄膜生长的研究利用激光分子束外延，它结合了传统的分子束外延条件与脉冲激光沉积。该项目的重点是：利用激光分子束外延技术生长表面形貌可控、缺陷浓度低的全应变锰氧化物薄膜，通过不同衬底控制薄膜中的应变，并对应变进行全面表征;并通过对磁性和磁输运性质的研究，揭示了应变对磁输运性质的影响机制，低场磁电阻（MR），以及锰氧化物材料的磁各向异性和MR各向异性。这些研究有望提供新的信息，以更好地了解大的低场磁电阻在应变MnO_2薄膜的起源，以及电子晶格耦合，磁和磁电阻各向异性的锰氧化物薄膜。该项目解决了材料科学领域的基础研究问题，具有很高的潜在技术相关性。这项研究的成功可能会导致基于磁阻的设备技术发展的进步。该计划的一个重要特点是通过在一个基本和技术上重要的领域对学生进行培训来整合研究和教育。 ***