Gy. Shitov et al., RAMAN-STUDY OF CRITICAL FLUCTUATIONS NEAR THE PHASE-TRANSITION IN FERROELECTRIC LI2GE7O15, Phase transitions, 46(3), 1994, pp. 143-161
The anomalous behavior of the soft mode in the Raman spectra of the Li
2Ge7O15 polar phase has been found to be in good agreement with renorm
alization group (RG) theoretical results in the short-range scaling re
gion 7 < T-c - T < 43 K. The values and the temperature dependence of
the dimensionless critical susceptibility, the order parameter correla
tion lengths along the orthorhombic axes and the bare soft phonon damp
ing constant have been obtained along with the scaling indexes nu = 0.
631 +/- 0.002, gamma = 1.23 +/- 0.03 and the Ginzburg parameter Gi app
roximate to 0.41 from a least-squares fit of the RG Formula to the Ram
an data.