Specific heat of high-purity solid gallium close to the melting point

Abstract

We report on specific heat determinations of 99.9999% pure gallium applying an optical A.C. method. Data were taken with a temperature resolution, relative to the melting point T,, of 2 mK, starting from 1.5 K below T, and proceeding across the melting transition. The specific heat which was derived from amplitude and phase measurements, increases below the nominal melting point. The implication of these findings is discussed.

Surface-induced melting and freezing II. A semi-empirical Landau-type model

“…For, if Ay > 0 ((~i/ (Jc~)l'~ > l), the surface region starts to disorder when A becomes smaller than A,,. That is, the disordering sets in as soon as the temperature becomes larger than the onset temperature To, with To defined by A,, = L,(l -To/T,) and given by (28) and (31). Clearly, for Ay > 0, & is smaller than T, and a surface melting transition appears in the temperature range To -c T < T,.…”

“…Experiments confirm the predictions of table 1. Surface-induced melting has been observed on crystals of Pb [5-9,25-281, Cu [29], Al [12,30], and Ga [31], while numerous undercooling experiments on a variety of elements indicate a general absence of surface freezing effects in liquids [18,20].…”