Materials Science and Engineering Colloquium
Date: October 09, 2015 from 11:00 am to 12:00 pm EDT
Location: Columbia University
Morningside Campus
S.W. Mudd, Room 214
Contact: For further information regarding this event, please contact Chris A. Marianetti by sending email to chris.marianetti@columbia.edu or by calling 212-854-9478.
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Patrick Woodward

Department of Chemistry and Biochemistry, Ohio State University

"The magnetism of osmate double perovskites: Unraveling superexchange interactions between 3d and 5d transition metal ions"

Double perovskites with stoichiometry A2MOsO6 (A2 = Sr, Ca, La; M = Mg, Cr, Fe, Co, Ni) and are a fascinating class of compounds whose properties can vary dramatically depending on the filling and relative energy levels of the d-orbitals on the 3d ion and the 5d orbitals on osmium. Differences in the energy levels of the 3d orbitals and the Os 5d orbitals causes the M−Os superexchange coupling through the eg orbitals to be insignificant, thereby allowing the Os−Os and M−M.superexchange coupling to be competitive. The strength of the competing superexchange interactions can be tuned by changing the filling of d-orbitals and are highly sensitive to changes in chemical pressure.  Using these tools we are able to access magnetic phases ranging from ferrimagnetism to antiferromagnetism to spin glasses.

Host: Chris Marianetti