Abstract
Two recent series of studies exemplified by Tokunaga, J. Phys. Soc. Jpn., 57, 4275 (1988); Venevtsev et al., Ferroelectrics, 130, 245 (1992) have made interesting proposals: 1) that Ferroelectrics do not have Curie temperatures much below 100 K (Tokunaga); and 2) that ferroelectrics have transition temperatures that are “quantized” in units of 12.5 K (Venevtsev). In the present note we argue that both are wrong and suggest instead alternative models: 1) that commensurate ferroelectrics satisfy a log-normal distribution of Curie temperatures; and 2) that incommensurate systems may more often than is recognized exhibit a Devil's staircase of transition that manifest themselves in subtle experiments (especially ultrasonic attenuation) as slightly aperiodic sequences of phases.