Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 45: Correlated Electrons: Poster Session
TT 45.73: Poster
Donnerstag, 29. März 2012, 15:00–19:00, Poster B
Critical behavior at the antiferromagnetic phase transition of Azurite — •P. T. Cong, B. Wolf, R. S. Manna, A. Brühl, S. Köhler, and M. Lang — Physikalisches Institut, J.W. Goethe-Universität Frankfurt, SFB/TR49, 60438 Frankfurt(M)
The natural mineral azurite has been considered as a model substance for a 1D spin 1/2 Heisenberg diamond chain [1]. However, early studies of this material indicate the presence of 3D long-range antiferromagnetic (AF) order below TN ∼ 1.88 K [2]. Clear signatures of the transition into the ordered phase have been observed in ultrasound, thermal expansion and specific heat measurement at TN. Here we present a detailed investigation of the critical behavior of the sound velocity and ultrasonic attenuation in the vicinity of TN. While the critical velocity changes exhibit a uniform behavior for various magnetic fields, the critical attenuation shows a sudden change as the system moves from the ordered AF to the spin-flop state. We compare the critical behavior derived from the ultrasonic studies with that observed in the specific heat and thermal expansion.
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