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Roles of two successive phase transitions in new spin-Peierls system TiOBr

T. Sasaki·M. Mizumaki·T. Nagai·T. Asaka·K. Kato·M. Takata·Y. Matsui·J. Akimitsu
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Abstract

In this sturdy, we determine the roles of two successive phase transitions in the new spin-Peierls system TiOBr by electron and synchrotron X-ray diffraction analyses. Results show an incommensurate superstructure along the h- and k-directions between Tc1=27K and Tc2=47K, and a twofold superstructure which is related to a spin-Peierls lattice distortion below Tc1. The diffuse scattering observed above Tc2 indicates that a structural correlation develops at a high temperature. We conclude that Tc2 is a second-order lock-in temperature, which is related to the spin-Peierls lattice distortion with the incommensurate structure, and that Tc1 is from incommensurate to commensurate phase transition temperature accompanying the first-order spin-Peierls lattice distortion.

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T. Sasaki, M. Mizumaki, T. Nagai, T. Asaka, K. Kato, M. Takata, Y. Matsui, J. Akimitsu. 2005-09-14. Roles of two successive phase transitions in new spin-Peierls system TiOBr. https://doi.org/10.1016/j.physb.2006.01.417

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