MSE Colloquium
Date: November 19, 2010 from 2:00 pm to 3:00 pm EST
Location: Room 214 in S. W. Mudd
Contact: For further information regarding this event, please contact APAM Department by sending email to seasinfo.apam@columbia.edu or by calling 212-854-4457.
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Multifunctional multiferroic oxides by design:
Closing the loop, from models in the computer to real materials in the lab

Craig J. Fennie
School of Applied and Engineering Physics, Cornell University

The discovery of materials displaying novel properties is the driving force behind continued scientific progress across many disciplines. Due to their highly tunable ground states, structurally and chemically complex oxides are a promising class of materials in which to realize new emergent phenomena that could not only challenge our current understanding of condensed matter but also provide real solutions for technological advances in for example the energy sciences and electronics. The traditional exploratory route to identify new phenomena, however, is quite demanding, as there are an enormous number of possible materials that have yet to be identified. Additionally, recent advances in synthesis techniques facilitate tailoring and enhancing the properties of complex materials at the atomic scale, greatly extending the design variables.

In this talk I will discuss examples of our theory-driven experimental pursuit for new complex oxide materials rarely found in nature - ferromagnetic-ferroelectric oxides in which a spontaneous magnetism not only coexists with but also is strongly coupled to a spontaneous electric polarization. Additionally I will discuss our most recent theoretical work in which we show how oxygen octahedron rotations, ubiquitous in perovskites and related materials, enable an electric field to globally and deterministically switch the magnetization 180o, a challenge that so far has not been realized in a multiferroic. The most surprising result of this study may be that the specific materials already exist in nature. I will argue that contrary to its historic role, theory should be the first step in the discovery of new phenomena as it provides a natural starting point and roadmap for synthesis of truly unprecedented materials.

Hosted by Prof. Chris Marianetti