Anomalous ferromagnetic behavior in the orthorhombic Li${}_3$Co${}_2$SbO${}_6$

Abstract

Monoclinic Li${}_3$Co${}_2$SbO${}_6$ has been proposed as a Kitaev spin liquid candidate and investigated intensively, whereas the properties of its polymorph, the orthorhombic phase, is less known. Here we report the magnetic properties of the orthorhombic Li${}_3$Co${}_2$SbO${}_6$ as revealed by dc and ac magnetic susceptibility, muon spin relaxation ($\mu$SR) and neutron diffraction measurements. Successive magnetic transitions at (115, 89 and 71) K were observed in the low field dc susceptibility measurements. The transitions below $T_N$ (= 115 K), are suppressed in higher applied fields. However, zero field, ac susceptibility measurements reveals distinct frequency independent transitions at about (114, 107, 97, 79 and 71) K. A long range magnetic ordered state was confirmed by specific heat, $\mu$SR and neutron diffraction measurements, all indicating a single transition at about 115 K. The discrepancy between different measurements is attributed to possible stacking faults and/or local disorders of the ferromagnetic zig-zag chains, resulting in ferromagnetic boundaries within the overall antiferromagnetic matrix.

9 pages, 9 figures. Accepted by Inor. Chem

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