Uniaxial pressure dependence of spin-Peierls transition temperature in CuGeO3

Neutron diffraction experiments were performed applying uniaxial pressure along the a-axis of a single crystal of CuGeO3. We observed an overall decrease of the spin-Peierls transition temperature (Tsp) with increasing uniaxial pressure with dTsp/dp= -5.0 K/GPa in contrast to the application of hydrostatic pressure, where an increase of Tsp was observed. The uniaxial pressure dependencies of Tsp were estimated along each principal axis by Winkelman et al. from the thermal expansion coefficients and the specific heat via the Ehrenfest relation. According to these results the uniaxial pressure along the a-axis strongly suppresses Tsp with dTsp/dp-4.2 K/Gpa. Our experimental result is consistent with the estimation within error. (author)