Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Poster II

MA 33.51: Poster

Freitag, 26. März 2010, 11:00–14:00, Poster B1

Magnetic Properties of the quasi-2D S=1/2 Heisenberg antiferromagnet [Cu(pyz)₂(HF₂)]PF₆ — •Mykhaylo Ozerov — Hochfeld-Magnetlabor Dresden (HLD), Forschungszentrum Dresden - Rossendorf, Dresden, Germany

We report on electron spin resonance, high-field 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 (including high-magnetic-field magnetization and the temperature-field phase diagram) are strongly affected by two-dimensional spin fluctuations, despite of onset of 3D long-range magnetic ordering at T_N≈ 4.4 K. The ESR magnetic excitation spectrum in the 3D ordered phase is studied in detail.

The work was made in collaboration with E. Čižmár, R. Beyer, M. Uhlarz, Y. Skourski, S.A. Zvyagin J. Wosnitza, J.L. Manson, J.A. Schluter.