Thermodynamics of the coupled spin-dimer system TlCuCl3 close to a quantum phase transition

Abstract

We present thermal expansion alpha, magnetostriction and specific heat C measurements of \tal, which shows a quantum phase transition from a spin-gap phase to a Neel-ordered ground state as a function of magnetic field around H_{C0}->4.8T. Using Ehrenfest's relation, we find huge pressure dependencies of the spin gap for uniaxial as well as for hydrostatic pressure. For T->0 and H->H_{C0} we observe a diverging Grueneisen parameter Gamma(T)=alpha/C, in qualitative agreement with theoretical predictions. However, the predicted individual temperature dependencies alpha(T) and C(T) are not reproduced by our experimental data.

6 pages including 7 figures, contribution to the III Joint European Magnetic Symposia 2006, San Sebastian

References in corpus (1)

• Spin-resonance modes of the spin-gap magnet TlCuCl_3

Cited by in corpus (5)

• Divergence of the Magnetic Grüneisen Ratio at the Field-Induced Quantum Critical Point in YbRh${}_2$Si${}_2$
• Diverging thermal expansion of the spin-ladder system (C${}_5$H${}_{12}$N)${}_2$CuBr${}_4$
• Anomalous thermal expansion and strong damping of the thermal conductivity of NdMnO${}_3$ and TbMnO${}_3$ due to 4f crystal-field excitations
• Spin-spin correlations of the spin-ladder compound (C${}_5$H${}_{12}$N)${}_2$CuBr${}_4$ measured by magnetostriction and comparison to Quantum Monte Carlo results
• The fraction of Bose-Einstein condensed triplons in TlCuCl3 from magnetization M(T,H)-data