Magnetostriction of the spin-Peierls compound CuGeOa
Leonyuk L.I., Levitin R.Z., Ponomarenko L.A., Snegirev V.V., Vasil'ev A.N., Dhalenne G., Revcolevschi A.
The longitudinal and transverse magnetostriction, λ, of the spin-Peierls compound CuGe03 in the ø — Å-plane was measured in magnetic fields up to 20 Τ both above and below the transition temperature T,p -14.3 K. It was found that for a given crystallographic direction the value of magnetostriction is weakly dependent on the magnetic field direction. In the uniform [/-phase at Τ > T,p, λ was negative and approximately equal in the b and Ó directions, while in the dimeriEed D-phase at Τ < ôÇÒ, λ was positive, and ìØ > ìÓ. At low temperatures, λ sharply increased at the magnetic field induced transition from dimerized to magnetic Μ-phase. Experimental data allow estimation of the stress derivatives of the antiferromagnetic intrachain exchange interaction parameter and of the stress dependencies of the critical field of the D — Af-phase transition. PACS: 75.30.Kz, 75.80.+q
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