Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 40: Poster Session Correlated Electrons
TT 40.44: Poster
Mittwoch, 13. März 2013, 15:00–19:00, Poster D
Local probe studies (ESR and NMR) on the BaAg2Cu[VO4]2 quantum magnet — •Y. Krupskaya1, M. Schäpers1, E. Vavilova1,2, A.U.B. Wolter-Giraud1, H.-J. Grafe1, V. Kataev1, A. Möller3, and B. Büchner1 — 1IFW Dresden, Germany — 2ZPhTI, Kazan, Russia — 3University of Houston, USA
BaAg2Cu[VO4]2 contains Cu(II) S=1/2 on a distorted triangular
lattice. DFT band structure calculations, quantum
Monte-Carlo simulations, and high-field magnetization measurements
show that the physics of this compound is determined by a
superposition of ferromagnetic and antiferromagnetic uniform spin
chains with nearest neighbour exchange couplings of JFM=−19 K and JAFM=9.5 K [1]. Here we report the study
of BaAg2Cu[VO4]2 by High-Field/Frequency Electron Spin
Resonance (HF-ESR) and Nuclear Magnetic Resonance (NMR)
spectroscopies, which probe the local magnetic properties. In the
HF-ESR measurements, we observe an anisotropic ESR spectrum
typical for the Cu(II) ions and determine the g-tensor, gparal=2.38 and gperp=2.06. Moreover, we see a
substantial shift of the ESR lines at temperatures below 40 K
indicating the presence of short range magnetic correlations. NMR methods allowed for the investigation of local magnetic fields, the T1 and T2
relaxation times of the 51V sites. A pronounced broadening of
the NMR line is observed at temperatures below 60 K which is
consistent with the ESR results. We discuss the local probe
results with relation to the thermodynamic studies and theory
calculations.
[1] A.A. Tsirlin et al. Phys. Rev. B 85, 014401 (2012)