Magnetization Plateau of an S=1 Frustrated Spin Ladder

Abstract

We study the magnetization plateau at 1/4 of the saturation magnetization of the S=1 antiferromagnetic spin ladder both analytically and numerically, with the aim of explaining recent experimental results on 3,3^′,5,5^′-tetrakis(N-tert-butylaminoxyl)biphenyl. We propose two mechanisms for the plateau formation and clarify the plateau phase diagram on the plane of the coupling constants between spins.