HYPERFINE INTERACTIONS AT THE Sr0.88Ba0.12HfO3 COMPOUND

R. E. ALONSO; C. HOROWITZ; A. LÓPEZ GARCÍA

HYPERFINE INTERACTIONS

Año: 2001 vol. 136 p. 541 - 544

0304-3843

Abstract The temperature dependence of the hyperfine parameters in a powder sample of the Sr0.88Ba0.12HfO3 compound has been investigated for the first time using perturbed angular correlation (PAC) spectroscopy. The time spectra were measured as a function of the temperature from 293 to 1273K. Activated 181Ta nuclei were used as hyperfine probes at the Hf sites. The analysis of the time spectra indicates the presence of two different surroundings for the Ta probes. The most populated site (f1 » 75% at laboratory temperature) was fitted with the usual static quadrupole hyperfine interactions found in most perovskite-type compounds. The resulting quadrupole frequency is wQ » 24 Mrad/s at this temperature. This frequency continuously decreases to nearly 9 Mrad/s at 1273 K. The other site has a large and temperature independent quadrupole frequency wQ » 120 Mrad/s that reversibly transforms into the first, at high temperatures. The second interaction is probably originating by some defect in the structure.