ACCRETION-INDUCED CRUST SCREENING FOR THE MAGNETIC-FIELD DECAY OF NEUTRON-STARS

We propose that accretion can induce a neutron star magnetic field dec ay because the ferromagnetic accreted matter screens the magnetic fiel d of neutron star. Our model results suggest that: (i) the surface mag netic field decay is inversely correlated with the accretion mass in t he X-ray binary accretion phase as Delta M-0.4, (ii) the 'Bottom Field Strength' of about 10(8) G can occur when the accreted matter has com pletely replaced the crust mass of neutron star, (iii) most of the ori ginal magnetic field is compressed into the beneath of the accreted ma tter, so the internal field strength is larger than the original field strength and (iv) the field-period relation is obtained which is cons istent with the evolutionary track of the binary X-ray sources.