ANOMALOUS RESISTIVITY OF SRTIO3 IN THE VICINITY OF ITS STRUCTURAL PHASE-TRANSITION TEMPERATURE

Resistivity measurements have been done for SrTiO//3 implanted with B ions (acceleration energy equals 100 KeV, dose equals 6 multiplied by 10**1**5 minus 1 multiplied by 10**1**7 ions/cm**2) at temperatures between about 90K and 120K. Anomalous increments in resistivity (excess resistivities) were observed in the vicinity of the structural phase transition temperature, 105 K. The temperature dependence of the excess resistivity is compared with theoretical excess resistivity due to soft-phonon modes. Both theory and experiments reveal similar behavior. From this, the anomaly is conceivably due to the soft-phonon modes, which drive the structural phase transition of SrTiO//3.