On the critical behaviour of ferromagnets

Using high-temperature series expansions, an attempt is made to characterize the behaviour of the Ising model of a ferromagnet in a non-zero magnetic field. The functional form derived can be used to pass to the low-temperature side of the Curie point, and hence to determine the low-temperature critical behaviour. As a result, it is suggested that there are two basic parameters, in terms of which critical indices for all thermodynamic properties can be expressed.