Magnetic-order-induced crystal symmetry lowering in ACr2O4 ferrimagnetic spinels.

@article{Bordcs2009MagneticorderinducedCS,
  title={Magnetic-order-induced crystal symmetry lowering in ACr2O4 ferrimagnetic spinels.},
  author={S{\'a}ndor Bord{\'a}cs and D{\'a}niel Varjas and Istv{\'a}n K{\'e}zsm{\'a}rki and Gy{\"o}rgy Mih{\'a}ly and Leonetta Baldassarre and A. Abouelsayed and C. A. Kuntscher and Kenya Ohgushi and Yasuhiro Tokura},
  journal={Physical review letters},
  year={2009},
  volume={103 7},
  pages={
          077205
        }
}
We demonstrate that the onset of complex spin orders in ACr2O4 spinels with magnetic and Jahn-Teller active A=Fe and Cu ions lowers the lattice symmetry. This is clearly indicated by the emergence of anisotropic lattice dynamics-i.e., by the pronounced phonon splittings-even when experiments probing static distortions fail. The crystal symmetry in the magnetic phase is reduced from tetragonal to orthorhombic for both compounds. The conical spin ordering in FeCr2O4 is also manifested in the… 

Figures from this paper

Magnons and a two-component spin gap in FeV2O4

The spinel vanadates have become a model family for exploring orbital order on the frustrated pyrochlore lattice, and recent debate has focused on the symmetry of local crystal fields at the cation

Spin-phonon coupling in highly correlated transition-metal monoxides

Abstract. We report on the optical response of the highly correlated transition-metal monoxides MnO, FeO, CoO and NiO in the far-infrared regime. The main focus is put on spin-phonon coupling

Coexistence of incommensurate and commensurate spiral orders and pressure effect on polycrystalline CoCr2O4

In this paper, we have investigated the magnetism of multiferroic CoCr2O4. With decreasing temperature, CoCr2O4 first undergoes a ferrimagnetic transition at TC then a long-range spiral spin

Magnetic and dielectric response of cobalt-chromium spinel CoCr2O4 in the terahertz frequency range

The nature of the phonon and magnon modes in the CoCr2O4 multiferroic with a cubic spinel structure has been studied using submillimeter spectroscopy and infrared Fourier spectroscopy. This paper

Substantially enhanced ferroelectricity in JT ion Cu2+-doped Co1–xCuxCr2O4 (0 ≤ x ≤0.4)

We investigate the effect of Jahn-Teller (JT) active Cu2+ ions on the structural, magnetic, and ferroelectric properties of Co1–xCuxCr2O4 (0 ≤ x ≤ 0.4). All the samples can be indexed with a cubic

Evolution of magnetic properties in the normal spinel solid solution Mg(1-x)Cu(x)Cr2O4.

The evolution of magnetic properties in the normal spinel oxides Mg(1-x)Cu(x)Cr2O4 is examined using magnetization and heat capacity measurements and a magnetic temperature-composition phase diagram of the solid solution series is presented.

Magnetoelectric and multiferroic properties of spinels

In the last two decades, significant progress has been made in combining ferroelectricity and magnetism in the same material. Usually, magnetism and ferroelectricity were thought of as independent
...

References

SHOWING 1-4 OF 4 REFERENCES

Density Waves In Solids

* The One-Dimensional Electron Gas * Materials * The Charge Density Wave Transition and Ground State: Mean Field Theory and Some Basic Observations * The Spin Density Wave Transition and Ground

Philos

  • Mag. 87, 3711
  • 2007

Acta Crystallogr

  • 10, 554
  • 1957

However, a cubic to orthorhombic structural change at T C seems to be incompatible with the second-order nature of the magnetic transition