Low dimensionality and magnetic frustration of Ni_5.15Sn_0.85(O₂BO₃)₂hulsite

Ni_5.15Sn_0.85(O₂BO₃)₂ hulsite has a complex magnetic transition at 180 K, one of the highest order temperatures among the oxyborates [1]. To characterize the low-dimensional properties of Ni_5.15Sn_0.85(O₂BO₃)₂ hulsite, we combine bulk techniques as x-ray diffraction, XAS, magnetic and specific heat with local probe ¹¹⁹Sn Mössbauer spectroscopy. Hulsite compounds are the less studied in the family of oxyborates, their properties are determined by planes instead of one-dimensional subunits as ladders in ludwigites or ribbons in warwickites. The transition metal ions in hulsite form two planar substructures, one is a rectangular lattice, responsible for the magnetic transition, the other is a triangular lattice, which does not order down to 3 K. The experimental results suggest a spin-liquid behavior for this subsystem. The two planar substructures coexist as independent magnetic subsystems down to the lowest temperatures of our experiments [1].

[1] C.P.C. Medrano et al., PRB 98, 054435 (2018)