title: Orbital-ordering-driven multiferroicity and magnetoelectric coupling in GeV₄S₈.
abstract: We report here the discovery of multiferroicity and large magnetoelectric coupling in the type I orbital order system GeV₄S₈. Our study demonstrates that this clustered compound displays a para-ferroelectric transition at 32 K. This transition originates from an orbital ordering which reorganizes the charge within the transition metal clusters. Below the antiferromagnetic transition at 17 K, the application of a magnetic field significantly affects the ferroelectric polarization, revealing thus a large magnetoelectric coupling. Our study suggests that the application of a magnetic field induces a metamagnetic transition which significantly affects the ferroelectric polarization thanks to an exchange striction phenomenon.
authors.affiliation: Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Bd. du Maréchal Juin, 14050 Caen Cedex 4, France.
authors.forename: Kiran
authors.initials: K
authors.lastname: Singh
authors.affiliation: Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Bd. du Maréchal Juin, 14050 Caen Cedex 4, France and Institut Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Simon
authors.affiliation: Institut Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble, France.
authors.forename: Elena
authors.initials: E
authors.lastname: Cannuccia
authors.affiliation: Institut Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble, France and Institut Néel, CNRS UPR 2940 Département MCBT, 25 avenue des Martyrs, BP 166, 38042 Grenoble Cedex 9, France.
authors.forename: Marie-Bernadette
authors.initials: MB
authors.lastname: Lepetit
authors.affiliation: Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, 2 rue de la houssinière, BP32229, 44322 Nantes Cedex 3, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Corraze
authors.affiliation: Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, 2 rue de la houssinière, BP32229, 44322 Nantes Cedex 3, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Janod
authors.affiliation: Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, 2 rue de la houssinière, BP32229, 44322 Nantes Cedex 3, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Cario