Berlin 2008 – wissenschaftliches Programm

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SYNF: Symposium Ferroic materials and novel functionalities

SYNF 2: Ferroic materials and novel functionalities II

SYNF 2.4: Hauptvortrag

Dienstag, 26. Februar 2008, 16:00–16:30, A 151

Electrical field control of ferromagnets using multiferroics — •Ramamoorthy Ramesh — Dept. of Materials Science and Engineering and Dept. of Physics, University of California, Berkeley, CA 94720

Complex perovskite oxides exhibit a rich spectrum of functional responses, including magnetism, ferroelectricity, highly correlated electron behavior, superconductivity, etc. The basic materials physics of such materials provide the ideal playground for interdisciplinary scientific exploration. Over the past decade we have been exploring the science of such materials (for example, colossal magnetoresistance, ferroelectricity, etc) in thin film form by creating epitaxial heterostructures and nanostructures. Among the large number of materials systems, there exists a small set of materials which exhibit multiple order parameters; these are known as multiferroics. Our goal is to be able to deterministically control the state of a ferromagnet with the application of an electric field, by using heterostructures that include multiferroic perovskites. Our model multiferroic is BiFeO3, which ahs ferroelectric and antiferromagnetic order well about room temperature. Our work so far has shown that the AFM order can be controlled through coupling with the ferroelectricity. The next step is to explore the coupling of a ferromagnet to this antiferromagnet through the exchange biasing concept. Ultimately, this will give us the opportunity to switch the state of a ferromagnet ( and therefore the spin polarization direction) by simply applying an electric field to the underlying antiferromagnetic ferroelectric. In this talk, I will describe our progress to date on this exciting possibility.