Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.66: Poster

Mittwoch, 24. März 2010, 14:00–18:00, Poster D1

Magnetic Properties of the quasi-2D S=1/2 Heisenberg antiferromagnet [Cu(pyz)₂(HF₂)]PF₆ — •M. Ozerov¹, E. Čižmár^1,2, S.A. Zvyagin¹, R. Beyer¹, M. Uhlarz¹, Y. Skourski¹, J.L. Manson³, J.A. Schlueter⁴, and J. Wosnitza¹ — ¹Hochfeld-Magnetlabor Dresden, FZ Dresden - Rossendorf, Dresden, Germany — ²Centre of Low Temperature Physics, P.J. Šafarik University, Košice, Slovakia — ³Department of Chemistry and Biochemistry, Eastern Washington University, Cheney, WA, USA — ⁴Materials Science Division, Argonne National Laboratory, Argonne, IL, USA

We report on ESR, magnetization, and specific-heat studies of [Cu(pyz)₂(HF₂)]PF₆ single crystals, identified as a quasi-two-dimensional spin-1/2 Heisenberg antiferromagnet. Our measurements revealed J_inter/J_intra≤ 0.063 and A/J∼ 0.003, where J_inter, J_intra, J are the interplane, intraplane and mean exchange interactions, respectively, and A is the anisotropy constant. It is argued that the magnetic properties of this material are strongly affected by two-dimensional spin fluctuations, despite of the onset of 3D long-range magnetic ordering at T_N≈ 4.4 K. The temperature-field phase diagram and ESR magnetic excitation spectrum in the 3D ordered phase of [Cu(pyz)₂(HF₂)]PF₆ will be discussed in detail.

This work was partly supported by the DFG and EuroMagNET (EU contract No. 228043)