Figure19

Figure 19. Temperature dependence of the EXAFS Debye-Waller factors (MSRDs) for the Cu-O and Cu-Ba atomic pairs in HgBa$$ {}_{2} $$CuO$$ _{4+\mathrm{\delta}} $$ (open circles in top two panels). The diffraction Debye-Waller factors (MSD) $$ {{\sigma }_{\mathrm{Cu}}}^2 $$ for Cu atoms (open diamonds) and $$ {{\sigma}_{\mathrm{Ba}}}^2 $$ and $$ {{\sigma}_{\mathrm{O}}}^2 $$ for Ba and O atoms (solid diamonds) are also plotted in the two panels. The Debye-Waller factors calculated from diffraction data for a perfectly correlated ($$ \rho = 1 $$) and uncorrelated ($$ \rho = 0 $$) motion are shown by up and down triangles, respectively. The lines are guides to the eye. The bottom panel shows the temperature dependence of the correlation coefficient for the Cu-O and Cu-Ba distances determined by comparing EXAFS and neutron diffraction Debye-Waller factors [refer to Equation (16)]. Figure taken from Ref.^[120]. © APS Publishing. Reproduced with permission. All rights reserved.