Neutron powder diffraction study of the two-dimensional triangular lattice antiferromagnet CuCrO₂

Abstract

An S = 9 Heisenberg antiferromagnet on a triangular lattice CuCr02, in which stacking of the triangular lattice of magnetic Cr atoms forms a layered rhombohedral antiferromagnet, is studied by neutron powder diffraction. In the paramagnetic phase the powder diffraction pattern shows asymmetry, which proves a two-dimensional character. In the ordered phase, magnetic Bragg scattering has large width, indicating that the scattering is distributed on a line ($4 b) with peaks where 5 takes integer values. Although the magnetic long-range order is established in the c plane, correlation in the c direction is finite or the modulation vector is distributed on the line. Intensity of magnetic reflections is consistent with the 120" structure in the a-c plane with moment (3.1 2 0 . 2 ) ~~.

Magnetic structure of CuCrO2: a single crystal neutron diffraction study

“…The correlation length is therefore larger than at least several hundredÅ. This result clearly disagrees with the conclusions from the powder diffraction measurements [10,11] (which were suggesting short range order along the L-direction).…”

“…The latter is in better agreement with the occurrence of 3-dimensional order, although it had been shown that an interlayer exchange has to be relatively small (<0.2meV) [24]. The maximum ordered moment in our model is 2.8(2) µ B which is close to the expected 3 µ B for the Cr 3+ ion and the reported values from the powder measurements [10,11]. An additional uncertainty for the absolute moment value from the single crystal measurements comes from the non-equal domain distribution.…”

“…The powder experiments found an incommensurate magnetic propagation vector τ = (0.329, 0.329, 0) based on the position of the (0, 0, 0) + τ reflection, and a broadening of some of the magnetic Bragg peaks which was attributed to short range correlations along the L-direction, either in the form of quasi 2-dimensionality [10] or stacking faults [11]. The measured powder intensities were best described with a proper-screw magnetic structure, although other magnetic structure models could not be unambiguously excluded.…”

Lattice dynamics and thermal transport in multiferroicCuCrO2

“…Lattice parameters and anisotropic atomic displacement parameters were refined at all temperatures. The lattice parameters exhibit temperature behaviors consistent with literature values, with the c-axis displaying a negative thermal expansion, and the a-axis displaying normal thermal expansion [10,41].…”

The Structural and Magnetic Properties of CuRh1−x Mn x O2 (0 ≤ x ≤ 0.1) Delafossite Oxide

“…The introduction of charge carriers, which is possible in some delafossite compounds, may further induce novel phenomena arising from the coupling between the magnetic and transport properties in the quasi-two-dimensional frustrated triangular lattice. The magnetic degeneracy was lifted and the no collinear magnetic structure was realized in the antiferromagnetic (AF) regime below the ordering temperature (T N ) to resolve the magnetic frustration [18,19]. This magnetic frustration appeared to be removed by the introduction of some trivalent cations in M-sites.…”