Domain walls are diamagnetic

It is shown that contrary to a recent claim in the literature by Iwazaki [Ferromagnetic Domain Wall and Primeval Magnetic Field, Nishogakusha Univ. report Nisho-96/4 (August 1996), hep-ph/9608448], the domain walls made of scalar field are diamagnetic due to presence of massless fermionic modes on the wall. The diamagnetism vanishes at high temperature. Thus the domain walls could produce no effect on a primordial magnetic field in the early universe.