Spinel Structure Oxide Thin Films and Interfaces

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Technical: This project focuses on thin film oxide heterostructures. The objective is to understand novel magnetic and electronic phenomena associated with the interface between two dissimilar transition metal oxides through achievement of atomically smooth spinel structure oxide interfaces. Understanding how imbalances in valence, bandwidth and interaction lengths at the interface give rise to charge redistribution and magnetic and orbital order at the interface different from the bulk forms the basis of the project. Isostructural complex oxide heterostructures provide model systems where imbalances in valence, bandwidth and interaction length will be systematically studied. The approach includes: (i) synthesis of atomically smooth, spinel structure oxide thin films; (ii) synthesis of isostructural heterostructures with atomically sharp interfaces; (iii) local electronic and magnetic characterization of surfaces and interfaces by X-ray magnetic circular dichroism (XMCD), photoemission electron microscopy (PEEM), X-ray resonant scattering (XAS), magnetic force microscopy (MFM), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS); and (iv) electronic transport and magnetic characterization of heterostructures. Fundamental understanding of the role of band structures, electron densities, and interaction length imbalances on charge redistribution and magnetic and orbital order at the interface different from the bulk is sought. New knowledge and understanding from this research is anticipated for oxide systems, and more broadly in interface physics and materials science. Non-technical: The project addresses basic research issues in a topical area of materials science having high technological relevance. The research will contribute basic materials science knowledge at a fundamental level to new understanding and capabilities for potential next generation electronic/magnetic devices. 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. The project includes graduate and undergraduate student activities in the laboratory and in the classroom through a magnetics curriculum which also extends to local high school students. An internship program will be continued with a local high school and the scope of this interaction is expected to grow over the next three years. Graduate and undergraduate students will have the opportunity to mentor these high school interns during parts of the school year and in the summer. In cooperation with physics teachers from the high school, a modular materials science curriculum will also be developed.