  The nucleation field for infinite magnetic nanotubes, in the case of a
magnetic field applied parallel to the long axis of the tubes, is calculated as
a function of their geometric parameters and compared with those produced
inside the pores of anodic alumina membranes by atomic layer deposition. We
also extended this result to the case of an angular dependence. We observed a
transition from curling-mode rotation to coherent-mode rotation as a function
of the angle in which the external magnetic field is applied. Finally, we
observed that the internal radii of the tubes favors the magnetization curling
reversal.
