Numerical Evidence for the Existence of a Phase Transition in a Two-Dimensional Exchange-Interaction Model

Abstract
High-temperature—low-field susceptibility series for the exchange-interaction model of ferromagnetism are analyzed by means of a reexpansion technique to obtain the ordering temperature. In particular, for all two-sublattice decomposible structures (e. g., linear chain, plain square, simple cubic, body-centered cubic) the formula kBTCJ=(125)(z52)(4S+3)1 reproduces our numerical results.