Abstract
The thermal-expansion coefficients α of the spin-Peierls cuprate have been measured along the three orthorhombic directions using a high-resolution capacitance dilatometer. We observe giant, strongly anisotropic anomalies at the spin-Peierls transition temperature () and spontaneous strains along all three crystal axes below . From the jumps of α and the specific heat we estimate large uniaxial pressure dependencies of , in particular for pressure applied perpendicular to the one-dimensional chains. In addition, we observe an anomalous temperature dependence of the thermal expansion above the transition showing a striking similarity to that of the magnetic susceptibility.
- Received 30 January 1995
DOI:https://doi.org/10.1103/PhysRevB.51.12884
©1995 American Physical Society