  We study theoretically the structure of domain walls in ferromagnetic states
on Mobius strips. A two-dimensional classical Heisenberg ferromagnet with
single-site anisotropy is treated within a mean-field approximation by taking
into account the boundary condition to realize the Mobius geometry. It is found
that two types of domain walls can be formed, namely, parallel or perpendicular
to the circumference, and that the relative stability of these domain walls is
sensitive to the change in temperature and an applied magnetic field. The
magnetization has a discontinuity as a function of temperature and the external
field.
