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TT: Tiefe Temperaturen
TT 34: Correlated Electrons: Spin Systems and Itinerant Magnets
TT 34.5: Talk
Friday, March 31, 2006, 11:15–11:30, HSZ 301
Helimagnetism and Weak Ferromagnetism in the Edge-Shared Chain Cuprate NaCu2O2 — •S.-L. Drechsler1, J. Richter2, A.A. Gippius3, A.N. Vasiliev3, A.A. Bush4, A.S. Moskvin5, J. Malek6, Yu. Prots7, W. Schnelle7, and H. Rosner7 — 1IFW-Dresden, 01171 Dresden, PF 270116, Germany — 2Universität Magdeburg, Germany — 3Moscow State University, Russia — 4Moscow Inst. of Radiotechnics, Electronics and Automation, Russia — 5Ural State University Ekaterinburg, Russia — 6FZU AVCR, Praha, Czech Rep. — 7MPI-cPfS Dresden, Germany
We report on susceptibility, magnetization, 23Na NMR, and specific heat data of the spin-chain material NaCu2O2 in the paramagnetic and ordered phases. Below 13 K, where a sharp field-dependent specific heat peak appears, the NMR lineshape points to an incommensurate static modulation of the local magnetic field consistent with a spiral arrangement of the Cu magnetic moments. At 2 K weak ferromagnetism with a small ordered moment of about 4· 10−3µB has been observed. LDA based estimates of exchange integrals reveal a large inchain frustration leading to a magnetic spiral.