Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 6: Quantum Magnets and Molecular Magnets (joint session TT/MA)
TT 6.3: Vortrag
Montag, 12. März 2018, 10:00–10:15, H 3010
In- & interchain exchange constants of Li2CuO2: the origin of the ferromagnetic inchain ordering — •S.-L. Drechsler1, R. Klingeler2, W. Lorenz2, R. Kuzian3, L. Hozoi1, R. Jadav1, J. Richter4, H. Rosner5, U. Nitzsche1, A. Tsirlin6, and S. Nishimoto1,7 — 1IFW-Dresden, Germany — 2Heidelberg University, Germany — 3Inst. f. Problems of Material Science, Kiev, Ukraine — 4MPI-PKS, Dresden, Germany — 5MPI-CPfS, Dresden, Germany — 6Augsburg University, Germany — 7TU Dresden, Germany
Li2CuO2 takes a special place among
frustrated chain compounds with edge-sharing CuO4 units and a
ferromagnetic (FM) nearest neighbor (NN) in-chain coupling J1 due to its ideal planar CuO2
chain structure and its well-defined 3D
Neél-type ordering below TN ≈ 9 K of adjacent chains whose magnetic moments are aligned
FM along the chains (b-axis).
There are only frustrating AFM interchain couplings (IC)
with adjacent
chains shifted by half a lattice constant b.
No room is left for strong unfrustrated IC in shtark
contrast with a recently proposed scenario [1].
The AFM IC with dominant NNN components
plays a decisive role in the stabilization of the FM alignment of the magnetic
moments along b.
Although weak, with 8 NNN IC it is significant enough to
prevent a competing non-collinear spiral type ordering.
We report realistic values of all relevant exchange constants
based on two DFT and quantum chemistry calculations in full accord with a spin-wave analysis of INS, RIXS, and magnetic susceptibility χ(T) data. The large J1 ≈ -230 K is ascribed to a sizable direct
FM Cu-O coupling Kpd ≈ 100 meV.
G. Shu et al., New J. Phys. 19, 023026 (2017).