Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 55: Correlated Electrons: Low-Dimensional Systems -Materials 2
TT 55.2: Talk
Thursday, March 14, 2013, 09:45–10:00, H21
Magnetoacoustic and pressure studies of frustrated distorted diamond chain compound azurite — •P. T. Cong, B. Wolf, R. S. Manna, U. Tutsch, M. de Souza, A. Brühl, and M. Lang — Physikalisches Institut, Goethe-Universität, SFB/TR 49, D-60438 Frankfurt
Measurements of ultrasound, thermal expansion and magnetic susceptibility measurements were carried out on a high-quality single crystal of distorted diamond chain compound azurite. The results show clear signatures of the magnetic energy scales involved [1, 2] and disclose two pronounced anomalies at ∼ 20 K and ∼ 5 K in accordance with literature results of magnetic susceptibility and specific heat data [1]. Huge anomaly of acoustic signal and thermal expansivity at TN = 1.88 K demonstrate that in this material the onset of long-range antiferromagnetic (AFM) ordering is accompanied by sizable structural distortions. From the analysis of the temperature dependence of elastic constant and results of the pressure dependence of the magnetic susceptibility an estimate of the strain dependence of the dominant magnetic exchange coupling can be derived. These results highlight the significant role of strain interaction in this compound. The field and temperature dependence of sound velocity and thermal expansion reveal a very complex magnetic structure of azurite at temperature below TN. Based on these measurements we map out a detailed B−T phase diagram.
[1] H. Kikuchi et al. Phys. Rev. Lett. 94, 227201 (2005).
H. Jeschke et al., Phys. Rev. Lett. 106, 217201 (2011)