2008/06/12 by Taro Nakajima, Setsuo Mitsuda, Toshiya Inami +7
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Ferroelectric and Piezoelectric Materials #Multiferroics and related materials #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.78.024106
published as Phys. Rev. B 78, 024106 (2008) (10 pages) · 11 pages, 9 figures, to be published in Phys. Rev. B
arxiv created 2008/06/12 · openalex publication_date 2008/07/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We have performed synchrotron radiation x-ray and neutron diffraction measurements on magnetoelectric multiferroic CuFe_1\ensuremath-xAlxO2 (x=0.0155), which has a proper helical magnetic structure with incommensurate propagation wave vector in the ferroelectric phase. The present measurements revealed that the ferroelectric phase is accompanied by lattice modulation with a wave number 2q, where q is the magnetic modulation wave number. We have calculated the Fourier spectrum of the spatial modulations in the local electric polarization using a microscopic model proposed by T. Arima [J. Phys. Soc. Jpn. 76, 073702 (2007)]. Comparing the experimental results with the calculation results, we found that the origin of the 2q-lattice modulation is not the conventional magnetostriction but the variation in the metal-ligand hybridization between the magnetic Fe3+ ions and ligand O^2\ensuremath- ions. Combining the present results with the results of a previous polarized neutron diffraction study [Nakajima et al., Phys. Rev. B 77, 052401 (2008)], we conclude that the microscopic origin of the ferroelectricity in CuFe_1\ensuremath-xAlxO2 is the variation in the metal-ligand hybridization with spin-orbit coupling.