Electron paramagnetic resonance studies of the impurity Fe3+ and Mn4+ centers indicate that the symmetry of the crystal structure of millimeter-scale strontium titanate plates above 105 K lowers in the bulk from cubic to tetragonal, different from that of the conventional low-temperature antiferrodistortive phase. It is shown that the effect does not originate from the residual stress; its magnitude (observed tetragonal distortion) and particular manifestations depend on plate orientation, surface quality and the geometry of a sample. Peculiarities of the observed phenomenon are presented and possible scenario of its realization is discussed.
@article{arxiv.2008.01460,
title = {Symmetry breaking in single crystal SrTiO$_3$ plates: EPR manifestations},
author = {Bulat F. Gabbasov and Irina N. Gracheva and Alexander A. Rodionov and Sergey I. Nikitin and Dmitry G. Zverev and Vladimir A. Trepakov and Alexandr Dejneka and Lubomir Jastrabik and Roman V. Yusupov},
journal= {arXiv preprint arXiv:2008.01460},
year = {2021}
}