Condensed Matter Physics Seminar

2 p.m., Thursday, September 28, 2006
Room 1201, Physics Building

 Improper Ferroelectrics as new Magnetoelectric Materials

Ivan Sergienko

(Oak Ridge National Laboratory)

Abstract:  A stunning magnetoelectric effect - the switching of electric polarization by magnetic field was reported in TbMnO3 and TbMn2O5 a few years ago [1,2]. A large number of related materials has been discovered since then. It is now understood that while there is no intrinsic ferroelectric instability in these compounds, the polarization appears due to its coupling to exotic magnetic order parameters that break inversion symmetry. Correspondingly, the polarization is sensitive to the field-induced magnetic phase transitions. I will discuss the possible microscopic mechanisms underlying magnetoelectric coupling in improper ferroelectrics and ways to enhance their ferroelectric properties, with the primary focus on perovskite manganites [3,4].

[1] T. Kimura et al., Nature 426, 55, (2003).

[2] N. Hur et al., Nature 429, 392, (2004).

[3] I.A. Sergienko and E. Dagotto, Phys. Rev. B 73, 094434 (2006).

[4] I.A. Sergienko, C. Sen, and E. Dagotto, cond-mat/0608025.

Host:  Drew
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