Exchange-striction associated with the elliptical proper helical magnetic structure in the ferroelectric phase of CuFe1−yGayO2

Terada, Noriki; Nakajima, Taro; Mitsuda, Setsuo; Matsuda, M.; Kakurai, Kazuhisa; Tanaka, Yoshikazu; Kitazawa, Hideaki

doi:10.1088/1742-6596/211/1/012005

Cited by 2 publications

(4 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Arima [8] has proposed that a charge transfer between the Fe and the O ions appears according to the hybridization. However, we have no evidence for a charge-transfer modulation so far [23]. If it exits, some resonant signature should have been observed at Fe K edge.…”

contrasting

confidence: 58%

“…This spatial modulation breaks the crystal symmetry and invokes the ferroelectricity in this compound. Actually, we have observed that superlattice reflection 0, 1 + 2q, 0 appears in non-resonant energies around Fe K absorption edge [23]. On the other hand, we have not found any signature of resonant intensity for reflection 0, 1 − 2q, 0 at O K absorption edge, yet.…”

contrasting

confidence: 56%

See 1 more Smart Citation

Incommensurate Orbital Modulation behind Ferroelectricity inCuFeO2

et al. 2012

View full text Add to dashboard Cite

CuFeO(2) is one of the multiferroic materials and is the first case that the electric polarization is not explained by the magnetostriction model or the spin-current model. We have studied this material using soft x-ray resonant diffraction and found that superlattice reflection 0 1-2q 0 appears in the ferroelectric and incommensurate magnetic ordered phase at the Fe L(2,3) absorption edges and moreover that the rotation of the x-ray polarization such as from σ to π or from π to σ is allowed at this reflection. These findings definitely provide direct evidence that the 3d t(2g↓) orbital state of Fe ions has a long-range order in the ferroelectric state. The spin-orbit interaction in Fe ions plays a crucial role to the ferroelectricity in CuFeO(2), coupling two nontrivial spin and orbital orders, both of which break the crystal symmetry.

show abstract

contrasting

confidence: 58%

contrasting

confidence: 56%

Incommensurate Orbital Modulation behind Ferroelectricity inCuFeO2

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Although some x-ray diffraction measurements have revealed superlattice reflections having 2Q modulation in the FEIC phase of CuFe 1−x X x O 2 [44][45][46] it was difficult to distinguish an orbital contribution from a normal charge scattering caused by lattice distortion. To overcome this difficulty, Tanaka et al performed soft x-ray resonant diffraction on CuFe 0.978 Ga 0.022 O 2 at the Fe L 2,3 absorption edges [47].…”

Section: Observation Of Incommensurate Orbital Ordering Inmentioning

confidence: 99%

“…A ferroelectric polarization along the hexagonal [1 1 0] axis is induced by magnetic field in the ferroelectric-incommensurate (FEIC) phase (7 T H 13 T) (see figure 3(c)) [18]. The mechanism regarding ferroelectric polarization has been extensively studied by bulk measurements [30][31][32], neutron scattering [19,[33][34][35][36][37][38][39][40][41][42][43], synchrotron x-ray diffraction [44][45][46][47] Terahertz spectroscopy [48], electron spin resonance [49][50][51], Mössbauer experiments [52] and some theoretical work [53][54][55][56][57][58][59][60][61][62][63], since the discovery of ferroelectric polarization in CuFeO 2 .…”

Section: Introductionmentioning

confidence: 99%

Spin and orbital orderings behind multiferroicity in delafossite and related compounds

Terada¹

2014

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Coupling between noncollinear magnetic ordering and ferroelectricicty in magnetoelectric multiferroics has been extensively studied in the last decade. Delafossite family compounds with triangular lattice structure provide a great opportunity to study the coupling between spin and electric dipole in multiferroics due to the variety of magnetic phases with different symmetry. This review introduces the magnetic and ferroelectric phase transitions in delafossite ferrites, CuFe(1-x)X(x)O(2) (X = Al, Ga), AgFeO(2) and the related compound α-NaFeO(2). In CuFeO(2), the ferroelectric phase appears under a magnetic field or chemical substitution. The proper screw magnetic ordering with the magnetic point group 21', which has been determined by detailed analysis in neutron diffraction experiments, induces the ferroelectric polarization along the monoclinic b axis in CuFeO2. The cycloidal magnetic orderings are realized in AgFeO(2) and α-NaFeO(2), which are of the point group m1' allowing polarization in the ac plane. The emergence of ferroelectric polarization can be explained by both the extended inverse Dzyaloshinsky-Moriya effect and the d − p hybridization mechanism. These mechanisms are supported by experimental evidence in CuFe(1-x)Ga(x)O2. The polarized neutron diffraction experiment demonstrated one-to-one correspondence between ferroelectric polarization and spin helicity, S(i) × S(j). The incommensurate orbital ordering with 2 Q wave vector, observed by the soft x-ray resonant diffraction experiment, proved that the spin-orbit interaction ties spin and orbital orders to each other, playing a crucial role for the emergence of ferroelectricity in CuFe(1-x)Ga(x)O2.

show abstract

Exchange-striction associated with the elliptical proper helical magnetic structure in the ferroelectric phase of CuFe_1−yGa_yO₂

Cited by 2 publications

References 13 publications

Incommensurate Orbital Modulation behind Ferroelectricity inCuFeO2

Incommensurate Orbital Modulation behind Ferroelectricity inCuFeO2

Spin and orbital orderings behind multiferroicity in delafossite and related compounds

Contact Info

Product

Resources

About