Magnetic properties of the S = 52 anisotropic triangular chain compound Bi3FeMo2O12

Competing magnetic interactions in low-dimensional quantum magnets can lead to the exotic ground state with fractionalized excitations. Herein, we present our results on an S = 5/2 quasi-one-dimensional spin system Bi3FeMo2O12. The structure of Bi3FeMo2O12 consists of very well separated, infinite zig-zag S = 5/2 spin chains. The observation of a broad maximum around 10 K in the magnetic susceptibility χ(T ) suggesting the presence of short-range spin correlations. χ(T ) data do not fit to S = 5/2 uniform spin chain model due to the presence of 2 nearest-neighbor coupling (J2) along with the 1 st nearestneighbor coupling (J1) of the zig-zag chain. The electronic structure calculations infer that the value of J1 is comparable with J2 (J2/J1 ≈ 1.1) with a negligible inter-chain interaction (J /J ≈ 0.01) implying that Bi3FeMo2O12 is a highly frustrated triangular chain system. The absence of magnetic long-range ordering down to 0.2 K is seen in the heat capacity data, despite a relatively large antiferromagnetic Curie-Weiss temperature θCW ≈ – 40 K. The magnetic heat capacity follows nearly a linear behavior at low temperatures indicating that the S = 5/2 anisotropic triangular chain exhibits the gapless excitations.