Dresden 2003 – scientific programme

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MA: Magnetismus

MA 16: Anisotropie, Magnetoelastizit
ät

MA 16.3: Talk

Wednesday, March 26, 2003, 15:45–16:00, HSZ/04

On Magnetic Anisotropy of GdBa₂Cu₃O_6+y Single Crystals — •Vladimir Narozhnyi^1,2, Dieter Eckert¹, Günter Fuchs¹, and Karl-Hartmut Müller¹ — ¹Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, PO Box 270116, D-01171 Dresden, Germany — ²Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow Region, 142190, Russia

An interesting problem is why some compounds based on Gd³⁺ ions (with zero orbital magnetic moment) unexpectedly show an appreciable magnetic anisotropy. Here the magnetic properties of high-quality Al-free nonsuperconducting GdBa₂Cu₃O_6+y (Gd-1236) single crystals grown by flux method have been studied. The magnetic anisotropy below the Néel temperature T_N≈ 2.3 K corresponds to the direction of Gd³⁺ magnetic moments along tetragonal c-axis. At T<T_N clear indications on a spin-flop transition for H∥ c have been observed on magnetization curves at H_sf≈ 10 kOe. Magnetic phase diagrams have been obtained for H∥ c as well as for H⊥ c. A pronounced anisotropy in the magnetic susceptibility (unexpected for Gd-based compounds) has been found above T_N. Possible reasons for the observed anisotropic behavior of Gd-1236 will be discussed.