Magneto-elastic couplings in the distorted diamond-chain compound azurite

Abstract

We present results of ultrasonic measurements on a single crystal of the distorted diamond-chain compound azurite Cu${}_3$(CO${}_3$)${}_2$(OH)${}_2$. Pronounced elastic anomalies are observed in the temperature dependence of the longitudinal elastic mode $c_{22}$ which can be assigned to the relevant magnetic interactions in the system and their couplings to the lattice degrees of freedom. From a quantitative analysis of the magnetic contribution to $c_{22}$ the magneto-elastic coupling $G$ = $\partial J_2$/$\partial {\epsilon }_b$ can be determined, where $J_2$ is the intra-dimer coupling constant and ${\epsilon }_b$ the strain along the intra-chain $b$ axis. We find an exceptionally large coupling constant of $|G|\sim ($3650 $\pm$ 150) K highlighting an extraordinarily strong sensitivity of $J_2$ against changes of the $b$-axis lattice parameter. These results are complemented by measurements of the hydrostatic pressure dependence of $J_2$ by means of thermal expansion and magnetic susceptibility measurements performed both at ambient and finite hydrostatic pressure. We propose that a structural peculiarity of this compound, in which Cu${}_2$O${}_6$ dimer units are incorporated in an unusually stretched manner, is responsible for the anomalously large magneto-elastic coupling.

9 pages, 6 figures

References in corpus (7)

• Possible Quasi-One-Dimensional Fermi Surface in La_{2-x}Sr_{x}CuO_4
• Nature of the spin dynamics and 1/3 magnetization plateau in azurite
• Hydrostatic-pressure tuning of magnetic, nonmagnetic and superconducting states in annealed Ca(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Dynamics of the Distorted Diamond Chain
• High-resolution thermal expansion measurements under Helium-gas pressure
• Magnetoelastic and structural properties of azurite Cu3(CO3)2(OH)2 from neutron scattering and muon spin rotation
• Critical Phenomena at the Antiferromagnetic Phase Transition of Azurite

Cited by in corpus (7)

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• Magneto-acoustic study near the quantum critical point of the frustrated quantum antiferromagnet Cs2CuCl4
• Magneto-structural properties of the layered quasi-2D triangular-lattice antiferromagnets Cs${}_2$CuCl${}_{4-x}$Br${}_x$ for $x$ = 0,1,2 and 4
• Thermal Conductivity and Spin State of the Spin Diamond-Chain System Azurite Cu3(CO3)2(OH)2
• Field-induced effects in the spin liquid candidate PbCuTe${}_2$O${}_6$