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Quantum magnetization plateaux of an anisotropic ferrimagnetic spin chain

Toru Sakai·Kiyomi Okamoto
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Abstract

The magnetization curve of the $(S,s)=(1,1/2)$ ferrimagnetic alternating spin chain with the single-ion anisotropy $D$ is investigated with the numerical exact diagonalization of finite clusters and size-scaling analyses. The system has a plateau at 1/3 of the saturation moment, which corresponds to the spontaneous magnetization for D=0. Varying $D$ in the 1/3-magnetized ground state under the external field along the axis of $D$, a quantum phase transition is revealed to occur at the critical value $D/J=1.114 \pm 0.001$ where the plateau vanishes. Except for the critical point, the plateau is always opening, but the mechanism is different between $D D_c$. The change of mechanisms is an evidence to clarify that the plateau originates from the quantization of magnetization.

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Toru Sakai, Kiyomi Okamoto. 2002-04-18. Quantum magnetization plateaux of an anisotropic ferrimagnetic spin chain. https://doi.org/10.1103/physrevb.65.214403

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