Strain Effects in Thin Manganite Films Grown by Laser-MBE

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.

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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.

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