title: Relaxations as key to the magnetocapacitive effects in the perovskite manganites.
abstract: We present a detailed dielectric study of the relaxation effects that occur in several perovskite rare-earth manganites, including the multiferroics TbMnO(3) and DyMnO(3). We demonstrate that the strong magnetocapacitive effects, observed for electrical fields E parallel c, are nearly completely governed by magnetic-state induced changes of the relaxation parameters. The multiferroic materials, which undergo a transition into a spiral magnetic state, show qualitatively different relaxation behavior than those compounds transferring into an A-type antiferromagnetic state. We ascribe the relaxations in both cases to the off-center motion of the manganese ions, which in the multiferroic systems also leads to the ferroelectric ordering.
authors.affiliation: Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86135 Augsburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Schrettle
authors.forename: P
authors.initials: P
authors.lastname: Lunkenheimer
authors.forename: J
authors.initials: J
authors.lastname: Hemberger
authors.forename: V Yu
authors.initials: VY
authors.lastname: Ivanov
authors.forename: A A
authors.initials: AA
authors.lastname: Mukhin
authors.forename: A M
authors.initials: AM
authors.lastname: Balbashov
authors.forename: A
authors.initials: A
authors.lastname: Loidl