title: Spin amplitude modulation driven magnetoelectric coupling in the new multiferroic FeTe2O5Br.
abstract: The magnetic and ferroelectric properties of the layered geometrically frustrated cluster compound FeTe2O5Br were investigated with single-crystal neutron diffraction and dielectric measurements. An incommensurate transverse amplitude modulated magnetic order with the wave vector q=(1/2,0.463,0) develops below T(N)=10.6(2) K. Simultaneously, a ferroelectric order due to exchange striction involving polarizable Te4+ lone-pair electrons develops perpendicular to q and to Fe3+ magnetic moments. The observed magnetoelectric coupling is proposed to originate from the temperature dependent phase difference between neighboring amplitude modulation waves.
authors.affiliation: Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Pregelj
authors.forename: O
authors.initials: O
authors.lastname: Zaharko
authors.forename: A
authors.initials: A
authors.lastname: Zorko
authors.forename: Z
authors.initials: Z
authors.lastname: Kutnjak
authors.forename: P
authors.initials: P
authors.lastname: Jeglic
authors.forename: P J
authors.initials: PJ
authors.lastname: Brown
authors.forename: M
authors.initials: M
authors.lastname: Jagodic
authors.forename: Z
authors.initials: Z
authors.lastname: Jaglicić
authors.forename: H
authors.initials: H
authors.lastname: Berger
authors.forename: D
authors.initials: D
authors.lastname: Arcon