Berlin 2008 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 13: Correlated Electrons: Low-dimensional Systems - Materials 1
TT 13.3: Talk
Tuesday, February 26, 2008, 10:00–10:15, H 2053
Low-dimensional spin-1/2 systems in complex vanadium phosphates — •Alexander Tsirlin1,2, Ramesh Nath1, Christoph Geibel1, and Helge Rosner1 — 1Max-Planck Institute CPfS, Dresden, Germany — 2Department of Chemistry, MSU, Moscow, Russia
Vanadium phosphates are known to reveal low-dimensional spin-1/2 systems and to provide unique realizations for some of the actively studied spin models like frustrated J1−J2 square lattice. Magnetic patterns of these compounds may be quite complicated as non-magnetic phosphate tetrahedra mediate superexchange interactions. The signs and the magnitudes of such interactions can hardly be estimated on structural basis only, therefore the choice of the appropriate spin model is sometimes very problematic. In our contribution we present the results of joint experimental (thermodynamic properties measurements) and computational studies of several complex vanadium phosphates. We employ full-potential band structure calculations in order to give reliable estimates of the exchange coupling constants. The estimates justify the choice of the particular model and help us to give reliable interpretation of the experimental data. We reach a remarkable agreement between the experimental and computational results. Our studies show that some of the vanadium phosphates are promising objects for the investigation of low-temperature quantum phenomena in low-dimensional spin-1/2 systems.
The Emmy-Noether program, GIF (I-811-257.14/03), and RFBR (07-03-00890) are acknowledged for financial support.