Structural and magnetic phase transitions in triclinic Ca10(FeAs)10(Pt3As8)

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Iron-arsenide superconductors are crucial in condensed matter physics.
• Understanding parent compounds is key to designing new superconductors.
• Ca10(FeAs)10(Pt3As8) is a parent compound for 1038-type superconductors.

Purpose of the Study:

• To investigate the structural and magnetic phase transitions in triclinic Ca10(FeAs)10(Pt3As8).
• To examine the effect of platinum doping on these transitions.
• To compare the transition behavior with other iron-arsenide parent compounds.

Main Methods:

• High-resolution X-ray diffraction to analyze structural changes.
• Muon spin rotation (μSR) experiments to probe magnetic ordering.
• Synthesis and characterization of platinum-doped samples (Ca10(Fe(1-x)Pt(x)As)10(Pt3As8)).

Main Results:

• A structural transition with splitting of in-plane lattice parameters was observed at approximately 120 K.
• Platinum doping (x=0.03) weakened the distortion and shifted the transition to 80 K.
• μSR experiments indicated the onset of magnetic order near the transition and a broad magnetic phase transition.
• The structural transition did not reduce space group symmetry but broke the local fourfold symmetry of FeAs-layers.

Conclusions:

• Ca10(FeAs)10(Pt3As8) exhibits unique structural and magnetic phase transitions.
• Platinum doping influences the transition temperatures and structural distortions.
• The findings provide insights into the mechanism of superconductivity in related iron-arsenides.