Lattice specific heats of cobalt and ruthenium

The nearest-neighbor central-force model of Srinivasan and Ramji Rao has been used to calculate the lattice specific heats of cobalt and ruthenium as a function of temperature. The frequency distribution function needed for the specific-heat calculations has been drawn by constructing a histogram involving a total number of 19 380 frequencies. The theoretical CVl values are compared with CVl values obtained from experimental data on the specific heat at constant pressure CP. There is reasonably good agreement between theory and experiment for both cobalt and ruthenium. The theoretical dispersion curves in the [0001] direction for ruthenium have been compared with the available experimental measurements and the agreement is fairly good except for one of the optical branches. © 1979 The American Physical Society.