We study the behavior of magnetization curve as a function of magnetic field
in the immediate vicinity of the magnetization plateaus of 1D electron systems
within the bosonization formalism. First we discuss the plateau that is formed
at the saturation magnetization of 1D electron system. Interactions between
electrons we treat in the lowest order of perturbation. We show that for
isolated systems, where total number of electrons is not allowed to vary,
magnetic susceptibility stays always finite away of half filling. Similar
statement holds for many other magnetization plateaus supporting nonmagnetic
gapless excitations encountered in 1D electron/spin systems in the absence of
special symmetries or features responsible for the mode decoupling. We
demonstrate it on example of the plateaus at irrational values of magnetization
in doped modulated Hubbard chains. Finally we discuss the connection between
the weak coupling description of saturation magnetization plateau and strong
coupling description of zero magnetization plateau of attractively interacting
electrons/ antiferromagnetically interacting spin 1 Bosons.Comment: 10 pages, 3 figures. To appear in Phys. Rev.
