Revisiting cubic and tetragonal SrTiO3-δ crystal structures with high-resolution thermal expansion
- Oliveira, F. S. [ Montana State University: Physics ]
- dos Santos, C. A. M.
- da Luz, M. S.
- Neumeier, J. J. [ Montana State University: Physics ]
High-resolution linear thermal expansion on pristine and vacuum-reduced SrTiO3-delta single crystals is reported for the temperature range 5 K < T < 300 K. A weak transition to a pseudocubic phase is observed near similar to 280 it may be a precursor to the transition to tetragonality occuring at 106 K. Using lattice parameter data for calibration, precise determination of the temperature-dependent lattice parameters from the linear thermal expansion data is enabled by a new method, despite the presence of twinning. The resulting data compare well with diffraction data. The distorcive angle phi, normally taken as the order parameter for the order-disorder transition, is obtained in the analysis. The results provide a data set with higher relative resolution and density than existing data.