Abstract
Using high resolution x-ray diffraction (XRD) on high purity powders, we resolved the structure and symmetry of the intriguing compound from room temperature down to 20 K to an unprecedented level of accuracy. Upon cooling, this set of data unambiguously reveals a second-order phase transition lowering the symmetry from tetragonal to orthorhombic at a temperature K. The observation of an orthorhombic distortion of the plane is attributed to nematic phase formation supported by local Jahn-Teller (JT) dynamical instability. At K, spins order and at K the tetragonal structure is recovered with an elongated axis.
- Received 19 August 2015
- Revised 6 November 2015
DOI:https://doi.org/10.1103/PhysRevB.93.125138
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