Powder X-Ray Reference Patterns of Sr2RGaCu2O y (R = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Y)

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• The study investigates lanthanide strontium gallium copper oxide (Sr2RGaCu2O y) phases, structurally analogous to the high-temperature superconductor Ba2YCu3O7.
• These compounds feature unique zig-zag tetrahedral GaO4 chains instead of the square planar Cu-O chains found in related structures.

Purpose of the Study:

• To perform X-Ray Rietveld refinements on eleven lanthanide-containing 2112 phases.
• To characterize the crystal structure and lattice parameters of these compounds.
• To investigate potential structural disorder within the GaO4 chains.

Main Methods:

• X-Ray Rietveld refinements were employed to analyze the crystal structure of eleven Sr2RGaCu2O y phases.
• Reference powder patterns were generated using the Rietveld decomposition technique.
• Electron diffraction studies were conducted on Sm- and Er-analogs to probe structural disorder.

Main Results:

• The unit cell volume of the studied compounds exhibits a trend consistent with lanthanide contraction.
• Lattice parameters were precisely determined, showing variations with different lanthanide elements (R).
• Electron diffraction revealed diffuse streaks along the b-axis in Sm- and Er-analogs, indicating disorder in the GaO4 chains.

Conclusions:

• The study successfully characterized the crystal structure of eleven lanthanide 2112 phases using X-Ray Rietveld refinements.
• The observed lanthanide contraction trend and lattice parameter variations provide valuable crystallographic data.
• Evidence of disorder within the GaO4 chains suggests further avenues for research into these materials.