Properties of spin polarized isospin symmetric nuclear matter and neutron matter

The properties of the spin polarized isospin symmetric nuclear matter and neutron matter as well as their equations of state are investigated by employing the Skyrme effective interaction with four sets of parameters SKM, SIII, SLy230a and SLy230b. Whichever Skyrme parameter is used, the ferromagnetic phase transitions are predicted in both the isospin symmetric nuclear matter and neutron matter. Above the critical density, the polarized matter becomes more stable than the unpolarized one. Consequently such a phase transition is one of the possible explanations of the strong magnetic field in neutron stars. In addition the magnetic susceptibility χ is also evaluated and the ratio χ/χF is obtained as a function of the density. The existence of an infinite discontinuity confirms the occurrence of a ferromagnetic phase transition once more