The technique of studying the synchrotron radiation scattering on single crystals over wide temperature range using an original miniature device for applying an electric field to a sample is described. A specific feature of the device is the possibility of its application with various heating and cooling systems. The technique was used at BM01 beamline at the European Synchrotron Radiation Facility (ESRF) for the study of the influence of electric field on the processes of structural transformation in lead zirconate–titanate single crystal with a low titanium concentration. The efficiency of the technique proposed in this work is demonstrated and the results of the preliminary analysis of the results are presented.

Results of X-ray diffraction in the intermediate ferroelectric phase of single crystal PbZr$_{0.993}$Ti$_{0.007}$O$_{3}$ are presented. Existence of M-type superstructures $q_{M}$ = \{$\frac{1}{2}$, $\frac{1}{2}$, 0\} and satellites around them, $q_{M}+\{\delta,\delta,\delta\}$, is confirmed. For the first time second order satellites $\{2\delta,2\delta,2\delta\}$ have been observed in the vicinity of $q_{M}$ and fundamental Bragg peaks. Structural model of regular system of antiphase domains is used for diffraction calculation. Calculated pattern includes M-type superstructures as well as first and second order satellites around $q_{M}$. It is shown that second order satellites around fundamental Bragg peaks could not be reproduced in the context of this model. The possible origin of the system of the superstructure reflection observed in the intermediate phase is discussed.