2D image of the x-ray diffraction pattern of the crystal, recorded at by a CCD detector in a selected region of plane (a). The diffraction spots were indexed using a tetragonal unit cell ( space group) (, ). Temperature evolution of the charge order superstructure peak intensity (indicated by an arrow) is shown in panel (b), revealing order-disorderlike broad transition.
Current-voltage phase shift (a) and modulus of complex dielectric impedance (b) of the sample, measured as a function of temperature at different frequencies. The dielectric permittivity at 1MHz are shown as an inset (panel b), along with the integrated intensity of the charge ordering superstructure [already shown in Fig. 1(b)].
FTs of the EXAFS oscillations (shown as inset) measured on the system at 10 and 300 K, showing in-plane atomic distribution around the Ni atom. The FTs are performed between and using a Gaussian window and not corrected for the phase shifts, representing raw experimental data. The peaks 1.6 Å are due to in-plane Ni–O bonds, while the peak at 3.2 Å represents Ni–La(Sr) scatterings. The peak at 3.4 Å is due to the Ni–O–Ni multiple scattering. The first shell fit is also shown (dashed line).
Temperature dependence of MSRD of the Ni–O pair determined by correlated DWFs , compared with the MSRD of Cu–O in . The dashed line is a fit and represents correlated Einstein model behavior with a temperature-independent (static) contribution. Data for (Ref. 30) are also shown.
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