Strain Effects in Thin Manganite Films Grown by Laser-MBE

本项目研究在晶格错配衬底上生长异质外延锰矿薄膜，以提供具有可控应变水平和可控形貌的伪晶薄膜，以评估应变对巨磁网电阻（CMR）的主要影响。薄膜生长研究利用激光MBE，它结合了传统的MBE条件和脉冲激光沉积。项目重点是：利用激光- mbe技术制备表面形貌可控、缺陷浓度低的全应变锰酸盐薄膜；通过使用不同的衬底来控制薄膜中的应变，并充分表征应变；并通过对磁性和磁输运性质的研究，揭示应变对磁输运性质、低场磁电阻（MR）、磁性和磁各向异性的影响机制。这些研究有望提供新的信息，以更好地了解应变超薄锰薄膜中大低场MR的来源，以及锰薄膜中的电子-晶格耦合，磁和磁各向异性。该项目涉及具有高潜在技术相关性的材料科学主题领域的基础研究问题。这项研究的成功可能会导致基于磁阻器件的技术发展的进步。该计划的一个重要特点是通过培养学生在一个基础和技术上重要的领域的研究和教育的整合。* * *

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. ***