Coupling Magnetism to Electricity in Multiferroic Heterostructures

12:30 PM - 01:30 PM
Ramamoorthy Ramesh, ORNL Deputy Director of Science and Technology
Oak Ridge Postdoctoral Association "Standing on the Shoulders of Giants" Research Seminar Series
Building 4500-N, Weinberg Auditorium (Room I-126)
Email: Tara M. Pandya

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 material systems, there exists a small set of materials which exhibit multiple order parameters; these are known as multiferroics. Using our work in the field of ferroelectric (FE) and ferromagnetic oxides as the background, we are now exploring such materials, as epitaxial thin films as well as nanostructures. Specifically, we are studying the role of thin film growth, heteroepitaxy and processing on the basic properties as well as magnitude of the coupling between the order parameters. In our work we are exploring the switchability of the antiferromagnetic order using this coupling.
What is the importance of this work? Antiferromagnets (AFM) are pervasive in the recording industry. They are used as exchange biasing layers in MTJ’s etc. However, to date there has been no antiferromagnet that is electrically tunable. We believe that the multiferroic BiFeO3 is one compound where this can be observed at room temperature. 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 magnetic state in 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.

About the speaker:

Dr. Ramesh completed his Ph.D. in Materials Science from the University of California, Berkeley. He is the recipient of several professional recognitions, including the Humboldt Senior Scientist Prize, Fellowship of the American Physical Society, Fellowship of the Materials Research Society, Fellowship of the American Association for the Advancement of Science, the MRS Turnbull Prize, and the APS McGroddy New Materials Prize. In 2011, he was elected to the U.S. National Academy of Engineering and in 2012 he was recognized as the Indian Institute of Science Distinguished Alumnus. He was the founding director of the U.S. Department of Energy’sSunShot Initiative that is aimed at bringing the cost of solar electricity to grid parity (~5c/kWh) through science and technology.

Refreshments will be served.
This talk will be followed by a Q&A session and ‘meet & greet’ with the speaker.
Contacts: Tara M. Pandya ( or Arnab Banerjee (


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