  Magnetization curves of the ferrimagnetic mixed spin-(1/2,S) Heisenberg
chains are calculated with the help of density-matrix renormalization group
method for several quantum spin numbers S=1, 3/2, 2 and 5/2. It is shown that
the ferrimagnetic mixed spin-(1/2,S) Heisenberg chains exhibit irrespective of
the spin value S exactly one intermediate magnetization plateau, which can be
identified with the gapped Lieb-Mattis ferrimagnetic ground state. The
magnetization plateau due to the Lieb-Mattis ferrimagnetism breaks down at a
quantum phase transition towards the Luttinger spin liquid, which is
characterized by a continuous change of the magnetization with the magnetic
field until another quantum critical point is reached at the saturation field.

Statistical Mechanics;Strongly Correlated Electrons