Dresden 2017 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 3: Focus: Ferroics with Mesoscopic Order

DF 3.6: Vortrag

Montag, 20. März 2017, 12:00–12:30, WIL B321

Superparamagnetism induced by polar nano region in relaxor magnet — •Minoru Soda — ISSP, Univ. of Tokyo, Japan

Strong coupling between magnetism and dielectricity has attracted much attention in the fundamental and applied physics. In order to search novel system exhibiting enhanced coupling between the dielectric and magnetic properties, we focused on relaxor ferroelectrics having magnetic ions, relaxor magnet. In the relaxor ferroelectrics, there is the concept of Polar Nano Regions (PNRs), where ordered polarizations in nanoscale domains are randomly oriented. In the present study, the interaction between PNRs and the magnetic correlation was studied both by macroscopic properties and microscopic neutron-scattering measurements for two different compounds; perovskite 2/3 BiFeO₃−1/3 BaTiO₃ and triangular lattice system LuFeCoO₄. As a result, the obvious coupling between nuclear and magnetic correlations was identified, and a novel type of superparamagnetism induced by PNR was discovered. The growth of the antiferromagnetic correlation with ferromagnetic component is restricted inside the PNRs and the magnetic moments in nano-magnetic domain behave as superparamagnetic moments. For relaxor magnet, the dielectric and magnetic properties were dominated by the Multiferroic Nano Region.