Erbium heat capacity

Lanthanide (III) Oxides. The lanthanide(III) oxides will be used to illustrate the present breadth of our most extensive knowledge of the chemical thermodynamics of lanthanide compounds. Cryogenic heat capacities of hexagonal (III) lanthanum, neodymium, and samarium oxides, together with those of cubic (III) oxides of gadolinium, dysprosium, holmium, erbium, and ytterbium, have been reported (90, 91, 195). In addition, those of thulium, lutetium, and a composition approaching that of cerium (III) oxide have also been determined, and five well-characterized compositions between PrOi.714 and PrOi.833 are currently under study (J93). 

Erbium has been scantily studied due to the usual problem of obtaining samples of sufficient purity, which here appears to have been more serious than for the other lanthanide metals. Widely conflicting results have been reported for the heat capacity of Er, which makes its presentation something of a hotchpotch. 

The magnetic term in the heat capacity is what would be expected from the ferromagnetic spiral (i.e. the cone) structure of erbium (Kaplan 1961) and has been supported by the discovery of a linear spin-wave dispersion law along the c-axis in neutron scattering experiments (Nicklow et al. 1971). 

Satya and Wei (1971) measured the heat capacities of hep erbium and thulium metals and three of their isostructural alloys from 1.3 and 4.2 K. They analyzed their data by a least squares method to fit the equation... 

The heat capacity from -267 to 27°C (60 to 300 K) of 9.65 at% Er-Lu alloy has been measured by Taylor et al. (1972) using an adiabatic calorimeter and a platinum resistance thermometer. The metals used in preparing the alloy were vacuum sublimed in tantalum at 10 torr and 1600°C for lutetium and 1400°C for erbium, then analyzed for impurities. The alloy was remelted several times to insure homogeneity, cast to a cylindrical shape and machined. After heat capacity measure-... 

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