High-pressure hydrothermal growth and characterization of Sr3Os4O14 single crystals

Single crystals of the novel strontium osmate Sr3Os4O14 have been grown by the hydrothermal method using opposed anvil high-pressure and high-temperature technique. The reaction took place in sealed gold capsules at 3 GPa and a temperature of 1100 degrees C, with water acting as a solvent. The employed method yields up to 1 mm crystals with quite uncommon double-terminated morphologies. The crystal structure was identified as tetragonal by single-crystal X-ray diffraction, with lattice parameters a = 12.2909(8) & ANGS; and c = 7.2478(5) & ANGS;. The structural analysis suggests P42nm or P42/mnm as a possible space group. In general, the structure belongs to the pyrochlore type and is composed of a network of symmetrically arranged OsO6 octahedra. Resistivity measurements evidence a metallic behavior, accompanied by a temperature-independent paramagnetism. Heat capacity measurements reveal a slightly enhanced value of the Sommerfeld coefficient & gamma; = 34 mJ/mol K2. Superconductivity has not been observed down to 2 K.

Automated summary

In this study, single crystals of a novel strontium osmate, Sr3Os4O14, were successfully grown using the hydrothermal method and opposed anvil high-pressure and high-temperature technique. The crystal structure was identified as tetragonal and belongs to the pyrochlore type. Resistivity measurements showed metallic behavior and temperature-independent paramagnetism. Heat capacity measurements revealed a slightly enhanced Sommerfeld coefficient of gamma = 34 mJ/mol K2. No superconductivity was observed down to 2 K.