Phase transitions in oxides studied by perturbed angular correlation spectroscopy

Radioactive atoms located on cation sites in oxide matrices can be used to monitor phase transitions by measuring the electric or magnetic hyperfine i nteractions by means of Perturbed Angular Correlations spectroscopy. The ar ticle illustrates three types of phase transitions studied with In-111 trac ers and their daughter nuclei Cd-111, namely magnetic, structural and REDOX phase transitions in binary and ternary polycrystalline or single-crystall ine oxides. In this context, we also discuss the question of identifying th e probes' lattice site(s), the scaling of the Electric Field Gradients in o xides, the influence of the (impurity) probes themselves on the phase trans itions, and the occurrence and mechanisms of dynamic interactions. Recent r esults on In-111 in pure and Li-doped In2S3 will also be presented.