Dresden 2009 – scientific programme
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MA: Fachverband Magnetismus
MA 38: Multiferroics
MA 38.5: Talk
Thursday, March 26, 2009, 16:15–16:30, HSZ 103
Quantum paraelectric-like behavior and giant magnetodielectric coupling in NdFe3(BO3)4 — •Umut Adem1, Liran Wang1, Norman Leps1, Rüdiger Klingeler1, Christian Hess1, Alexander Vasiliev2, Leonard N. Bezmaternykh3, and Bernd Büchner1 — 1Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Germany — 2Moscow State University, Moscow, 119992, Russia — 3Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russia
We have measured the dielectric constant in addition to specific heat, magnetostriction, and magnetization of magnetoelectric NdFe3(BO3)4 single crystals and observed rare quantum paraelectric-like behavior. The dielectric constant increases with decreasing temperature in the temperature range 300 to 5K, more sharply upon the magnetic ordering of Fe spins below 30 K. Application of magnetic field strongly suppresses the additional increase below TN, resulting at 5K, 8 % change in the dielectric constant under 3 Tesla. We speculate that the dielectric behavior originates from soft phonon mode behavior and the coupling of this soft phonon mode to the magnetic ordering causes the giant magnetodielectric coupling. We compare the quantum paraelectric (incipient ferroelectric) behavior and the magnetodielectric coupling of NdFe3(BO3)4 to that of TbFe3(BO3)4 single crystals.