We report low temperature thermodynamic, magnetic and electron spin resonance (ESR) measurements on single crystal samples of a quantum spin chain material Rb₂Cu₂Mo₃O₁₂. In heat capacity measurement, phase transitions to magnetically ordered state are clearly observed, and the entire phase diagram is mapped out in detail. It is found that the criticalities of the transitions at lower and upper fields are dominated by three-dimensional order and one-dimensionality, respectively. The measured phase boundaries and ESR data prove that anisotropy heavily influences the magnetic state of Rb₂Cu₂Mo₃O₁₂ [1].
[1] S. Hayashida et al., Phys. Rev. B 100, 134427 (2019).