PNNL

Abstract

Perovskite materials, such as SrTiO3, are of broad interest for applications ranging from electronic devices to the immobilization of high-level nuclear wastes. As a result, there is renewed interest in developing a fundamental understanding of irradiation and implatation effects on the properties and performance of SrTiO3. In this study, low-energy (40 keV) H? was implanted into single crystal SrTiO3 at ~ 120 K over a range of ion fluences. Rutherford Backacattering Spectroscopy in channeling geometry (RBS/C) was used to investigate the ion-beam-induced disordering and recovery processed in the irradiated SrTiO3. The resonant nuclear reaction, 1H(19F, alpha-gamma)16O, was used to profile the implanted H. For annealing temperatures up to ~570 K, isochronal annealing results indicate increasing disorder on the Sr, Ti, and O sublattices with temperature in the vicinity of the implanted hydrogen, possibly as a result of reaction of the implated hydrogen with the lattice. This increased disorder showed evidence for recovery at 570 K and decreased with further increases in annealing temperature up to 770 K. isochronal annealing at 870 K resulted in a uniform increase in the backscattering yield across the penetration depth of the implant hydrogen. Scanning electron microscopy (SEM) showed that blisters (or bubble-like platlets) of several microns diameter formed below the surface of the SrTiO3 after the 870 K anneal; thus deforming the surface above the blister. The blisters most likely contain H2. Such blistering is a well-known phenomenon in gas-implanted metals and was extensively investigated in the 1970's. This may be the first reported observation for blistering in a crystalline oxide. Secondary ion mass spectroscopy (SIMS), and Infrared spectroscopy (IR) measurements are planned to charaterize the nature of the chemical bonding in the implanted region. These results will be discussed in detail.