Superconductivity at 23 K in Pt doped BaFe₂As₂ single crystals

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Chemistry

Background:

• BaFe2As2 is an iron-pnictide superconductor exhibiting magnetic ordering and structural transitions at 139 K.
• Substitution of Fe in BaFe2As2 can suppress magnetic ordering and induce superconductivity.
• Group VIII element substitution in BaFe2As2 systems is a known route to explore superconductivity.

Purpose of the Study:

• To synthesize and characterize a new iron-pnictide superconductor, BaFe(1.90)Pt(0.10)As(2).
• To investigate the effect of platinum substitution on the magnetic and superconducting properties of BaFe2As2.
• To confirm the bulk nature and evaluate the superconducting properties of the newly discovered material.

Main Methods:

• Single crystal growth using a self-flux solution method.
• Characterization through x-ray diffraction, transport measurements, magnetic susceptibility, and specific heat measurements.
• Analysis of structural, magnetic, and thermodynamic properties to identify superconductivity.

Main Results:

• Superconductivity was successfully induced in BaFe(1.90)Pt(0.10)As(2) with a critical temperature (Tc) of 23 K.
• The substitution of 5% Fe with Pt completely suppressed the magnetic ordering and structural transition observed at 139 K in BaFe2As2.
• Full diamagnetic screening and a specific heat jump at Tc confirmed the bulk nature of the induced superconducting phase.
• Key superconducting parameters, including critical fields and their temperature dependence, were found to be comparable to other substituted BaFe2As2 systems.

Conclusions:

• Platinum substitution is an effective method for suppressing magnetic order and inducing bulk superconductivity in the BaFe2As2 system.
• The discovered BaFe(1.90)Pt(0.10)As(2) exhibits robust superconducting properties comparable to other transition metal-substituted analogs.
• This work highlights the potential of Group VIII element substitution for tuning the electronic properties and achieving superconductivity in iron-based materials.