Magnetic Anisotropy of SrCu₂(BO₃)₂with a Two-Dimensional Orthogonal Dimer Lattice

Anomalous Magnetizations in Single Crystalline SrCu2(BO3)2

“…The obtained Weiss constant is slightly larger in magnitude than the previous results for the polycrystal (−92.5 K) 3) and for the field-oriented polycrystal along the c axis (−97.8 K). 4) When the temperature is decreased, the susceptibilities reach a maximum at about 15 K, decrease abruptly and then tend to approach zero at 0 K, achieving the exact dimer ground state. There is a Curie-like upturn below 4 K, presumably due to a defect in the crystal.…”

“…1) SrCu 2 (BO 3 ) 2 has a two-dimensional structure, which consists of alternately stacked CuBO 3 -and Sr-layers. 2) The peculiar magnetic network of the magnetic Cu 2+ ions (d 9 , thus S = 1/2), in which neighboring Cu 2+ -Cu 2+ dimers are orthogonally connected in the layer, has given rise to amazing aspects with respect to the ground state: [3][4][5] SrCu 2 (BO 3 ) 2 is a highly frustrated two-dimensional spin-gap system with a gap ∆ of about 30 K. Irrespective of the interdimer interaction, the direct product of the dimer singlets is the exact ground state, realizing the Shastry-Sutherland model 6) proposed almost 20 years ago. Moreover, a recent theory 7) revealed that this compound resides in the vicinity of the critical point between the gapped exact dimer state and the gapless Néel-ordered state.…”

“…The excited states of SrCu 2 (BO 3 ) 2 are also of great interest as seen in the magnetizations: we observed quantized magnetization plateaux at 1/4 and 1/8 of the saturation of the Cu moment M s . [3][4][5] The superstructures for the 1/4 and 1/8 plateaux are illustrated in Figs. 1(a) and 1(b), respectively.…”

Degeneracy of the 1/8 Plateau and Antiferromagnetic Phases in the Shastry-Sutherland Magnet TmB4

“…Among the FPPs that such theories need to replicate, the 1/8-FPP has presented a puzzle. While both the Heisenberg SrCu 2 (BO 3 ) 2 as well as Ising TmB 4 exhibit this phase in both thermodynamic 8,9,[22][23][24][25][26][27][28][29][30] 10,27 , and charge transport 30 , and the major features are shown in the inset of and hysteresis in the value of the magnetization in the plateau region, as opposed to the location of its boundaries, is seen. In this region, Siemensmeyer et al 27 and Wierschem et al 29 observe M/M sat fractions of 1/7, 1/9, and 1/11, in addition to 1/8.…”

Cu-NMR study of the quasi-one-dimensional magnet Cu3Mo2O9

“…Quantum fluctuation and frustration often bring unexpected effect on the magnetic order of spin system, such as Bose-Einstein condensation of delocalized magnons in three dimensionally coupled antiferromagnetic dimer system [1] or Wigner crystallization in frustrated spin system on the ShastrySoutherland lattice [2]. The subject of this paper is to investigate the effect of the quantum fluctuation and frustration on the spin system that bears two degrees of freedom coupling with each other.…”