title: Giant spin-driven ferroelectric polarization in TbMnO3 under high pressure.
abstract: The recent research on multiferroics has provided solid evidence that the breaking of inversion symmetry by spin order can induce ferroelectric polarization P. This type of multiferroics, called spin-driven ferroelectrics, often show a gigantic change in P on application of a magnetic field B. However, their polarization (<~0.1 μC cm(-2)) is much smaller than that in conventional ferroelectrics (typically several to several tens of μC cm(-2)). Here we show that the application of external pressure to a representative spin-driven ferroelectric, TbMnO3, causes a flop of P and leads to the highest P (≈ 1.0 μC cm(-2)) among spin-driven ferroelectrics ever reported. We explain this behaviour in terms of a pressure-induced magnetoelectric phase transition, based on the results of density functional simulations. In the high-pressure phase, the application of B further enhances P over 1.8 μC cm(-2). This value is nearly an order of magnitude larger than those ever reported in spin-driven ferroelectrics.
authors.affiliation: Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Aoyama
authors.affiliation: ISIR-SANKEN, Osaka University, Ibaraki, Osaka 567-0047, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Iyama
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR-SPIN), 67100 L'Aquila, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Picozzi
authors.affiliation: KYOKUGEN, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kimura