On the Vibrational Spectrum and the Vibrational Specific Heat of a Binary Superlattice Alloy

The change in the vibrational modes of a binary superlattice alloy due to the change in its own degree of order has previously been discussed. It was then expected that the vibrational specific heat of the superlattice alloy would change in response to the change in its own degree of order. Using the result obtained formerly, we have applied, in the present paper. Houston's approximate method of finding the frequency distribution function N(ν) to the calculation of the vibrational specific heat of β-brass in the state of any specified degree of order. It is shown that the vibrational specific heat of the disordered alloy is generally larger than that of the ordered one at oridnary temperatures. If two kinds of atoms which are the components of alloy are nearly equal in mass, the vibrational specific heat of the ordered alloy becomes larger than that of the disordered one at low temperatures.