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Tabata lab.

Tabata lab. M1 Kouji Tsuruta. Abstract. In general, the covalent bond between the anions and cations plays a key role in establishing the dipolar arrangement. In LuFe2O4, the electric dipole depends on electron correlation. electron.

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Tabata lab.

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  1. Tabatalab. M1 Kouji Tsuruta

  2. Abstract In general, the covalent bond between the anions and cations plays a key role in establishing the dipolar arrangement. In LuFe2O4, the electric dipole depends on electron correlation. electron the charge, spin and orbital degrees of freedom of the electron multiferroic materials ( which have ferroelectric and ferromagnetic property )

  3. Introduction RFe2O4 (R: rare-earth { Dy , Lu , Y } ) RFe2O4 is considered to be a charge-frustrated system of triangular lattices.

  4. possible model of the superstructure of Fe2+ and Fe3+ in RFe2O4 The competing interactions between frustrated charges are settled by this charge arrangement. the centres of Fe2+ (excess electron) and Fe3+ (electron deficiency) do not coincide in the unit cell of the superstructure. the possibility of ferroelectricity

  5. resonant X-ray scattering (RXS) experiment, in order to clarify the existence of the superstructure of Fe2+ and Fe3+ the anomalous atomic scattering factors of Fe2+ and Fe3+ The formation of the long-range ordering of Fe2+ and Fe3+

  6. Property of ferroelectrocity magnetic transition The limit of superstructure The ferroelectricity is developed by the polar arrangement of Fe2+ and Fe3+.

  7. Concerning the shoulder of the electric polarization at 250K In general, magnetic ordering hardly affects electric polarization. Polarization formed by the polar arrangement of Fe2+ and Fe3+ may allow such coupling. connected to magnetization This shoulder demonstrates a potential multiferroic property.

  8. Concerning the ferroelectric character Large dielectric dispersion This is a common feature of ErFe2O4. order–disorder type of ferroelectric materials Motion of the ferroelectric domain boundary gives rise to the dispersion.

  9. Arrhenius relation and Mossbauer measurement The polarization fluctuation correspond with the electron fluctuation. the dielectric dispersion Mossbauer measurement The ferroelectric domain boundary movement proceeds with the exchange of electrons between Fe2+ and Fe3+. proof of ferroelectricity from iron valence ordering

  10. Summary • LuFe2O4 has switching of electric polarization and large dielectric constant—are consistent with a criterion for the existence of ferroelectricity. • The order parameter of the electric polarization is the ordering of Fe2+ and Fe3+ in an arrangement of polar symmetry. • The dielectric dispersion shows a typical character of order–disorder type ferroelectric materials where the ferroelectric domain boundary proceeds with electron exchange between Fe2+ and Fe3+.

  11. outlook design future ferroelectric devices • control with charge, spin and orbital multiferroic material • polarization switching with the electron motion fatigue-free solid charge capacitor

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