High-pressure hydrothermal growth and characterization of Sr3Os4O14 single crystals

TL;DR

This paper reports the hydrothermal growth of novel Sr3Os4O14 single crystals under high pressure, their structural characterization, and initial physical property measurements indicating metallic behavior and paramagnetism.

Contribution

It introduces a new hydrothermal synthesis method for Sr3Os4O14 crystals and provides detailed structural and physical property data.

Findings

Crystals grown up to 1 mm with unique morphology

Structure identified as tetragonal pyrochlore type

Metallic behavior with paramagnetism observed

Abstract

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 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) A and c = 7.2478(5) A. 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 34 mJ/mol K2. Superconductivity has not been observed down to 2 K.