A Structural Study of Strain Effects in Manganite Films

This individual investigator award will support a project with the goal of providing insight into the intimate coupling of electron spin, electron transport and atomic structure in the manganite system, possibly leading to the development of more accurate models of systems with strong electron-lattice correlations. The long-range, nanoscale and local atomic structure will be determined in films ranging from the nanoscale to bulk-like to explore how magnetic and transport properties are influenced by substrate strain and film thickness. The structure will be determined via a variety of techniques including, x-ray diffraction, atomic force microscopy, and x-ray absorption spectroscopy. Direct comparisons will be made with corresponding bulk materials and correlations of the structure with resistivity and magnetization measurements will be performed. These materials may be of use in future magnetic read-head technologies. Graduate and undergraduate students will be involved in all levels of this work. To develop scientific literacy in students, a seven week summer research and teaching program on transition metal oxide preparation and characterization designed for Newark area high school students and teachers will be conducted during each year of this grant.

The manganite system is a class of materials that exhibit large changes in resistivity with applied magnetic field. These changes are an order of magnitude larger than those in sensors currently used in computer hard drives and may enable significantly higher storage capacity. However, the sensitivity at low magnetic fields required for use in hard drives must be improved. From the basic scientific perspective, these materials provide an important testing ground for systems with large correlations between atomic structure and electron transport. This individual investigator award will support a study of a broad range of films relevant to both technological applications and basic science understanding. The goal is to understand how magnetic properties are influenced by substrate strain and film thickness. Graduate and undergraduate students will be involved in all levels of this work. A seven-week summer research and teaching program on transition metal oxide preparation and characterization, designed for Newark area high school students and teachers will be conducted during each year of this grant. This will serve to develop scientific literacy and may influence students to pursue careers in science.