Dielectric properties of polycrystalline and single crystal (100) strontium titanate from 4 to 295 K.

The dielectric properties of single crystal and polycrystalline SrTiO₃ (ST) were investigated from 295 to 4 K. Relative permittivity (ε_r) and loss tangent (tan(δ)) were measured systematically as a function of direct current (DC) voltage (0 V/cm to 800 V/cm), frequency (100 Hz to 1 MHz), and temperature (295 K to 4 K) for type (100) single crystal SrTiO₃ (SC-ST) and for polycrystalline SrTiO₃ (PC-ST). Calculated equivalent series resistance (ESR) data are also reported. Overall, the permittivity of ST showed a dependence on temperature, DC voltage, and frequency. Dependences on voltage and frequency were only observed at temperatures below about 40 K. Curie–Weiss temperature (T_cw) was found to be independent of measurement frequency and applied DC field for SC-ST and PC-ST. Two frequency-dependent ESR peaks were observed for the SC-ST. There were five such peaks for PC-ST including the same two peaks displayed by SC-ST. All loss peaks were found to follow an Arrhenius type behavior. While certain peaks might be related to structural phase transitions, the additional peaks observed for PC-ST were attributed to the presence of grain boundaries, domains, residual porosity, impurities, or their combined effects. The results provide a good prediction of the dielectric performance of SrTiO₃ based capacitors towards optimizing the design of circuits used for cryogenic electronic applications. [ABSTRACT FROM AUTHOR]