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Change in lattice modulation upon gigantic magnetoelectric transition in GdMnO3 and TbMnO3

T. Arima·T. Goto·Y. Yamasaki·S. Miyasaka·K. Ishii·M. Tsubota·T. Inami·Y. Murakami·Y. Tokura
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Abstract

Single-crystal synchrotron x-ray diffraction measurements in strong magnetic fields have been performed for magnetoelectric compounds GdMnO3 and TbMnO3. It has been found that the P || a ferroelectric phase induced by the application of a magnetic field at low temperatures is characterized by commensurate lattice modulation along the orthorhombic b axis with q = 1/2 and q = 1/4. The lattice modulation is ascribed to antiferromagnetic spin alignment with a modulation vector of (0 1/4 1). The change of the spin structure is directly correlated with the magnetic-field-induced electric phase transition, because any commensurate spin modulation with (0 1/4 1) should break glide planes normal to the a axis of the distorted perovskite with the Pbnm space group.

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T. Arima, T. Goto, Y. Yamasaki, S. Miyasaka, K. Ishii, M. Tsubota, T. Inami, Y. Murakami, Y. Tokura. 2005-08-24. Change in lattice modulation upon gigantic magnetoelectric transition in GdMnO3 and TbMnO3. https://arxiv.org/abs/cond-mat/0508580

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