Magnetic contribution to the Gibbs energy of elements versus temperature and pressure

A model for the pressure and temperature dependence of the magnetic contributions to the Gibbs energy of ferromagnetic and antiferromagnetic elements is presented. These contributions are described by three parameters: (1) a critical temperature which is represented by the Curie temperature for ferromagnetic elements or Néel temperature for antiferromagnetic elements, (2) the pressure dependence of that critical temperature, (3) the average magnetic moment per atom. Using thermal expansion data, all these parameters and consequently the pressure and temperature dependence of the magnetic contribution can be calculated. Nickel, a ferromagnetic element, is used as an example.