Počet záznamů: 1

THz and infrared studies of multiferroic hexagonal Y.sub.1-x./sub.Eu.sub.x./sub.MnO.sub.3./sub. (x = 0 - 0.2) ceramics

  1. 1.
    0353097 - FZU-D 2011 RIV GB eng J - Článek v odborném periodiku
    Goian, Veronica - Kamba, Stanislav - Kadlec, Christelle - Nuzhnyy, Dmitry - Kužel, Petr - Moreira, J.A. - Almeida, A. - Tavares, P.B.
    THz and infrared studies of multiferroic hexagonal Y1-xEuxMnO3 (x = 0 - 0.2) ceramics.
    Phase Transitions. Roč. 83, 10-11 (2010), s. 931-941 ISSN 0141-1594
    Grant CEP: GA ČR(CZ) GA202/09/0682
    Výzkumný záměr: CEZ:AV0Z10100520
    Klíčová slova: multiferroics * infrared and THz spectroscopy * phonons
    Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
    Impakt faktor: 1.006, rok: 2010

    We report an investigation of hexagonal Y1-xEuxMnO3 ceramics with x=0, 0.1 and 0.2 using infrared and THz spectroscopies in the temperature range between 5 and 900 K. The temperature dependence of the THz permittivity reveals a kink near the antiferromagnetic phase transition temperature TN  70 K giving evidence of a strong spin-lattice coupling. Below TN two absorption peaks were revealed in the THz spectra close to 43 and 73 cm-1. While the first peak corresponds to a sharp antiferromagnetic resonance exhibiting softening on heating towards TN, the second one may be attributed to an impurity mode or a multiphonon absorption peak. High-temperature THz spectra measured up to 900 K reveal only small gradual increase of the permittivity in agreement with a weak phonon softening observed in the infrared reflectance spectra upon heating. This corresponds to an improper ferroelectric character of the phase transition proposed from first principle calculations by Fennie and Rabe.
    Trvalý link: http://hdl.handle.net/11104/0192437