Nuclear relaxation in CoGa3 lattice structures
Perturbed Angular Correlation (PAC) Spectroscopy is a method utilized to study hyperfine interactions within solids by observing the gamma rays emitted by the nuclear decay of probe atoms that have been artificially infused into the crystal structure. The IIIIn is a highly advantageous probe atom to use because its intermediate stage, IIICd, is relatively long lived and therefore provides researchers ample time to observe interactions. The purpose behind studying these hyperfine interactions is to gain a better understanding of atom diffusion in solids, whose properties (such as magnetic or electrical) often depend upon the distribution of atoms/elements. Through PAC, one can gain a better understanding of solids and their uses . The specific purpose of this project was to investigate the crystals of the CoGa3 structure and observe changes across different crystals. Samples were prepared using an arc furnace and then placed into the PAC to run for 6-10 (sometimes longer) days. CoGa3 structures contain two Ga (or In as the case might be) sites so two signals were expected and received. The curious aspect of the research was the relaxation frequency. The In3Rh and In3Ru seem to have a relaxation frequency crossover between the two sites while the In3Ir contained a shift from one iridium boundary to the other. The reason behind these occurrences is probably caused by the change in composition over time as the III In decays.