Phase Transition in a Compressible Ising Ferromagnet

Within the droplet model for the Ising spin system it is shown that the magnetic specific heat $C_p$ and the susceptibility ${\chi }_p$ for constant vanishing pressure and magnetic field remain finite in a compressible lattice as the critical point $T_c$ is approached from below. This regularization of $C_p$ and ${\chi }_p$ is caused by the long-range indirect spin-spin interaction, which is a consequence of the dependence of the exchange integral on the lattice spacing.