Larmor diffraction measurement of the temperature dependence of lattice constants in CuGeO3

Nicolas Martin (1) , L. P. Regnault (2) , S. Klimko (3) , Emilio Lorenzo (4) , R. Gahler (5)

1 MDN - Magnétisme et Diffusion Neutronique
2 SPSMS - UMR 9001 - Service de Physique Statistique, Magnétisme et Supraconductivité
3 LLB - UMR 12 - Laboratoire Léon Brillouin
4 NEEL - MagSup - Magnétisme et Supraconductivité
5 ILL - Institut Laue-Langevin

By using the neutron Larmor diffractionmethod and a setup based on the improvedneutron resonant spin echooption ZETA recently installed on the three-axis spectrometer IN22 (CRG beam line at the ILL), we have determined the precise relative evolution of the inter- and intra-chain lattice constants of the paradigmatic spin-Peierls compound CuGeO3 as a function of temperature. Our results are consistent with previous results obtained by conventional high-resolution diffraction. This method also allows to retrieve independently the sample mosaicities, as well as the widths of various lattice-spacings distributions, thus offering an evaluation of the intrinsic sample quality. In spite of the good definition of the spin-Peierls transition at T_{SP}=14.1(1) K in our sample, we observe a large distribution of lattice constants (\Delta d/d ~ 3 10^{- 3}), while the mosaicity of the sample appears to be quite reasonable (\le 20 minutes).

Mots clés: Neutron Larmor diffraction; High-resolution neutron diffraction; Spin-Peierls transition

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Nicolas Martin, L. P. Regnault, S. Klimko, Emilio Lorenzo, R. Gahler. Larmor diffraction measurement of the temperature dependence of lattice constants in CuGeO3. Physica B: Condensed Matter, 2010, 406 (12), pp.2333-2336. ⟨10.1016/j.physb.2010.10.006⟩. ⟨hal-00976866⟩