A new high pressure form of Ba3NiSb2O9

TL;DR

This paper reports the synthesis and characterization of a new high-pressure form of Ba3NiSb2O9 with a different stacking structure that preserves Ni planes but exhibits trigonal symmetry, relevant for quantum spin liquid research.

Contribution

It introduces a novel high-pressure phase of Ba3NiSb2O9 with a distinct stacking arrangement and symmetry, expanding the understanding of its structural variants.

Findings

New high-pressure phase with trigonal symmetry

Preservation of Ni triangular planes

Absence of magnetic order confirming QLS potential

Abstract

The interest in finding experimental realization of Quantum Liquid Spin phases leads us to elaborate polycrystalline samples of the 6H-B phase of Ba3NiSb2O9 . This structure shows Ni triangular planes and the first magnetic characterizations confirm the absence of any magnetic order as expected for QLS. The samples were synthesized by treatment under HP-HT of the 6H-A phase of Ba3NiSb2O9. The optimized synthesis conditions were 2.5 GPa and 620{\deg}C. By combining several technics as XRD, NPD and TEM we show that even the obtained compound is in fact a new form of Ba3NiSb2O9, that corresponds to a new stacking along c. This preserves the presence of Ni planes but results in a loss of the hexagonal symmetry. The TEM is helpful to conclude to a trigonal symmetry at a scale of 10nm.