Typical spontaneous symmetry breakdown in solid state as revealed by Fe3O4

S. Iida, M. Mizoguchi, Shinichiro Umemura, J. Yoshida, K. Kato, K. Yanai

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9 Citations (Scopus)


Several of our experimental results, as seen from the side of the symmetry breakdown of this most characteristic material, will be shown. X-ray study reveals that the lattice constant decreases approximately by 7×10 -6 per degree from room temperature to the Verwey temperature T v. At Tv, the cell volume increases by about 6×10-4, suggesting the presence of covalent nature in the crystal. At Tv, the crystal transforms to monoclinic. Although there is a report of another transition at about 12°K, very careful work by X-ray and NMR showed no discontinuous change in this temperature region in the accuracy up to 10-4. Detailed measurements of magnetoelectric effect were performed at 4.2°K and up to 34°K statically and dynamically. The induced electric potentials between the two planar electrodes formed parallel to a-, b-, or c-plane were observed as a function of the direction of the magnetic field in a-plane. Magnetic field cooling along [112], squeezing along [111] and electrically polarizing along a-, b-, or c-axis were simultaneously performed. We found that the electrically polarizing at and below Tv is only effective along a-axis. The crystal symmetry revealed is nearly monoclinic and may be triclinic. Again no appreciable discontinuous signal is observed near 12°K.

Original languageEnglish
Pages (from-to)7584-7586
Number of pages3
JournalJournal of Applied Physics
Issue numberB11
Publication statusPublished - 1979 Dec 1

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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