2008/02/22 by Andrea Gauzzi, A. Gauzzi, Gauzzi, A. +30
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #High-pressure geophysics and materials #Inorganic Chemistry and Materials #Rare-earth and actinide compounds #cond-mat.mtrl-sci #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.0802.3273
9 pages, 3 figures
arxiv created 2008/02/22 · arxiv updated 2009/12/01
By means of synchrotron X-ray diffraction, we studied the effect of high pressure, P, up to 13 GPa on the room temperature crystal structure of superconducting CaC6. In this P range, no change of the pristine space group symmetry, R\=3m, is found. However, at 9 GPa, i.e. close to the critical value at which a large Tc reduction was reported recently, we observed a compressibility jump concomitant to a large broadening of Bragg peaks. The reversibility of both effects upon depressurization and symmetry arguments give evidence of an order-disorder phase transition of second order, presumably associated with the Ca sublattice, which provides a full account for the above Tc reduction.