Magnetostriction of the spin-Peierls compound CuGeO3

The magnetostriction λ of spin-Peierls compound CuGeO3 was measured in magnetic field up to 18 T both above, and below the transition temperature Tsp=14.3 K. In uniform phase at T>Tsp λ in b-c plane is negative and isotropic, while in dimerized phase at T λc). At low temperatures λ increases sharply at transition from dimerized to magnetic phase.