Effects of the inter-layer couplings for the orthogonal dimer system SrCu2(BO3)2 are discussed. The spin-gap Δ of the three-dimensional model is independent of the inter-layer couplings when they are small. Therefore at low temperatures (T<Δ) thermodynamic properties are described well by the two-dimensional model. On the other hand at high temperatures the mean-field type scaling ansatz is useful to discuss the magnetic susceptibility for week inter-layer couplings. From fit of the magnetic susceptibility, the estimated coupling constants are J = 85 K for the nearest-neighbor couplings, J′=54 K for the next-nearest-neighbor couplings, and J′′=8 K for the inter-layer couplings. These parameters are consistent with the temperature dependence of the specific heat at low temperatures.
@article{arxiv.cond-mat/0004260,
title = {Thermodynamic Properties of Three-Dimensional Orthogonal Dimer Model for SrCu$_2$(BO$_3$)$_2$},
author = {Shin Miyahara and Kazuo Ueda},
journal= {arXiv preprint arXiv:cond-mat/0004260},
year = {2019}
}
Comments
4 pages, 9 figures, to appear in Supplement B to J. Phys. Soc. Jpn {\bf 69} (2000) Proceedings of the International Workshop "Magnetic Excitations in Strongly Correlated Electrons"