Magnetization plateau in the frustrated spin ladder

The magnetization process of the S = 1/2 antiferromagnetic spin ladder with the next-nearest-neighbor exchange interaction at T = 0 is studied by the exact diagonalization of finite clusters and size scaling analyses. It is f ound that a magnetization plateau appears at half the saturation value due to the frustration in the presence of sufficiently large rung coupling. The magnetization curves are also presented in several cases. (C) 2000 Elsevie r Science B.V. All rights reserved.