Dresden 2003 – wissenschaftliches Programm
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MA: Magnetismus
MA 4: Kondo / Schwer-Fermionen / Quasi-Niedrigdimensionale Systeme (gemeinsam mit TT)
MA 4.5: Vortrag
Montag, 24. März 2003, 11:15–11:30, HSZ/405
ESR Study of Exchange Interactions in Sr2V3O9 — •V.A. Ivanshin1,2, V. Yushankhai 1, J. Sichelschmidt1, D.V. Zakharov2, E.E. Kaul1, and C. Geibel1 — 1Max-Planck-Institut für Chemische Physik fester Stoffe, D-01187 Dresden, Germany — 2MRS Laboratory, Kazan State University, 420008 Kazan, Russia
The low-dimensional Vanadium-oxide Sr2V3O9 was studied using electron spin resonance (ESR) with a Bruker ELEXSYS E500 spectrometer. Sr2V3O9 single crystals were obtained by a flux technique. The ESR of the V4+-ion revealed that the spin-orbit interaction is quenched by a strong axial crystal field. A drastic ESR line broadening due to critical fluctuations was observed below 50 K, quite far from the Neel temperature TN = 5.8 K. Temperature and angular dependencies of the ESR linewidth have been investigated in the temperature range 4.2 ÷ 500 K. The ESR data interpretation is based on the combined application of an improved standard ESR theory for low-dimensional systems and an updated theory using hidden symmetry in the chain model with the spin S = 1/2. The ESR behavior in the temperature range 50 ÷ 500 K can be well described by the two most important contributions due to the Dzyaloshinsky-Moriya (DM) interaction and symmetric anisotropic exchange. Analysis of the observed angular dependence of the ESR linewidth allows us to predict a distribution of DM vectors in the magnetic chain.