Magnetization plateaus in weakly coupled dimer spin system

• Published in: arXiv.org
• Main Author: Kolezhuk, Alexei K
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 28.10.1998
• Subjects: Dimers; Magnetic saturation; Magnetization; Magnetization curves; Two dimensional models
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.9806292

I study a spin system consisting of strongly coupled dimers which are in turn weakly coupled in a plane by zigzag interactions. The model can be viewed as the strong-coupling limit of a two-dimensional zigzag chain structure typical, e.g., for the \((ac)\)-planes of KCuCl_3. It is shown that the magnetization curve in this model has plateaus at 1/3 and 2/3 of the saturation magnetization, and an additional plateau at 1/2 can appear in a certain range of the model parameters; the critical fields are calculated perturbatively. It is argued that for the three-dimensional lattice structure of the KCuCl_3 family the plateaus at 1/4 and 3/4 of the saturation can be favored in a similar way, which might be relevant to the recent experiments on NH_4CuCl_3 by Shiramura et al., J. Phys. Soc. Jpn. {\bf 67}, 1548 (1998).