Evidence for random strain at the cubic site of Yb3+ in palladium by Mössbauer spectroscopy on 170Yb

2014 We have analysed the slow relaxation Mössbauer emission spectrum obtained at T = 0.11 K of the paramagnetic ion Yb3+ in palladium. In this alloy, the two Yb3+ lowest crystal field states (ground state 03937 and first excited state 03938) are quasi-degenerate (separation 0394 ~ 2.5 K). In this situation the magnetic hyperfine spectrum is very sensitive to crystal field distortions away from cubic symmetry, which gives rise to an important static broadening of the lines. Our lineshape analysis provides an estimate of the product of the magnetoelastic constant V and the mean square deviation 03C3 of the random strain distribution : V 03C3 = 0.04 K. The spectrum lineshape suggests that the predominant distortions in PdYb have 03935 symmetry. In addition, we put in evidence finer effects related to the hyperfine interaction when treated to second perturbation order. J. Physique 46 (1985) 1553-1563 SEPTEMBRE 1985,