Abstract
We present the first direct measurements of as a function of uniaxial stress (i=a,b,c) along the crystal axes for an untwinned single crystal. is linear in with slopes /=-2.0±0.2 K/GPa, /=+1.9±0.2 K/GPa, and /=-0.3±0.1 K/GPa. These results confirm predictions based on thermal expansion measurements [C. Meingast et al., Phys. Rev. Lett. 67, 1634 (1991)] and show that the small hydrostatic pressure dependence of in is due to a cancellation of large and opposite effects in the a-b plane.
- Received 3 June 1992
DOI:https://doi.org/10.1103/PhysRevLett.69.2130
©1992 American Physical Society