Abstract
We present a detailed investigation of the magnetic properties of the spin- system by means of magnetic susceptibility and specific heat. Our experimental results show that in short-range antiferromagnetic (AFM) correlations appear near and two successive long-range AFM phase transitions are observed at and . The frustration factor indicates that the system is moderately frustrated, which is identifiable by the broken triangular symmetry within both and planes for the triclinic crystal structure. The magnetic isotherm at temperatures below shows a field-induced spin-flop transition, and a complete phase diagram for the two-step AFM system is mapped. Ab initio band-structure calculations suggest that the strongest exchange coupling does not correspond to the shortest Co-Co distance along the axis but rather along the diagonal direction through a Co-O-W-O-Co supersuperexchange path within the plane.
3 More- Received 19 October 2014
- Revised 9 November 2014
DOI:https://doi.org/10.1103/PhysRevB.90.174430
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