Magnetic susceptibility and magnetization properties of asymmetric nuclear matter in a strong magnetic field

We study the effects of a strong magnetic field on the proton and neutron spin polarization and magnetic susceptibility of asymmetric nuclear matter within a relativistic mean-field approach. It is shown that magnetic fields B similar to 10(16)-10(17) G have noticeable effects on the range of densities of interest for the study of the crust of a neutron star. Although the proton susceptibility is larger for weaker fields, the neutron susceptibility becomes of the same order or even larger for small proton fractions and subsaturation densities for B > 10(16) G. We expect that neutron superfluidity in the crust will be affected by the presence of magnetic fields.