Giant magnetoelectric effect in the Jeff=1/2 Mott insulator Sr2IrO4

Strong spin-orbit, crystal field, and Coulomb interactions compete to drive a narrow-gap Mott state in Sr2IrO4. Our study of the magnetic, thermal, and electrical properties of single-crystal Sr2IrO4 reveals a giant magnetoelectric effect (GME) arising from a frustrated magnetic/ferroelectric state below 240 K. The GME features (1) a strongly enhanced electric permittivity that peaks near a newly observed magnetic anomaly at 100 K, and (2) a large magnetodielectric shift (100%) near a metamagnetic transition. (C) 2010 American Institute of Physics. [doi:10.1063/1.3362912]