Magnetism in the Kitaev quantum spin liquid candidate RuBr3

The present studies show that long-range magnetic order takes place in RuBr3 at ≈34 K. The observations of clear oscillations in the muon time spectra demonstrate the presence of well-defined internal fields at the muon sites. The magnetic ordering appears to be very robust and static, suggesting a more conventional nature of magnetic ordering in the RuBr3 system at zero field. Present investigations prove that in RuBr3 the Kitaev interactions are likely to be weakened at zero field in comparison to the α-RuCl3 system. This proves that it is possible to tune the Kitaev interactions by replacing Cl with heavier halogen elements such as Br.