title: Electric-field switching of a magnetic propagation vector in a helimagnet.
abstract: We report novel magnetoelectric properties of a quantum-spin helimagnet Ba2CuGe2O7 with a noncentrosymmetric (but nonpolar) crystal structure. It was found that the spin helicity of the cycloidal spin order is always fixed to the lattice, therefore the magnetic propagation vector k determines the sign of electric polarization in Ba2CuGe2O7. Consequently, not only the magnetic-field drive of the ferroelectric domain but also the electric-field switching of magnetic k vector can be achieved.
authors.affiliation: Multiferroics Project, ERATO, Japan Science and Technology Agency (JST), c/o Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Murakawa
authors.forename: Y
authors.initials: Y
authors.lastname: Onose
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura