Renormalization of Critical Exponents in a Compressible Ising Model

The critical behavior of a compressible Ising system of the Baker-Essam type is examined for positive pressures. In addition to satisfying the assumptions of Fisher's theory of renormalization of critical exponents, the model, allows one to calculate the temperature region around $T_c$ where the renormalized exponents should show up. The region is $\Delta T_{\times }\sim {\left(P{J}_1^2\right)}^{\frac{1}{\alpha }}$ for small pressures, where $J_1$ is the spin-lattice coupling and $\alpha$ is the specific-heat exponent of the corresponding rigid Ising system.