Synthesis and HRTEM Investigation of EuRbFe₄As₄ Superconductor

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• EuRbFe4As4 is an iron-based superconductor exhibiting coexisting superconductivity and long-range magnetic ordering.
• Understanding the interplay between these phenomena is crucial for designing advanced superconducting materials.

Purpose of the Study:

• To investigate the atomic structure of as-grown EuRbFe4As4 crystals.
• To characterize the nature and superconducting properties of intrinsic nanoinclusions.
• To determine the role of these nanoinclusions in the superconducting mechanism.

Main Methods:

• High-resolution transmission electron microscopy (HRTEM) for atomic structure analysis.
• Magnetization measurements at low temperatures with magnetic field applied parallel to the ab plane.

Main Results:

• HRTEM revealed two-dimensional intrinsic nanoinclusions of the RbFe2As2 (122) phase, comprising ~5.6% of the crystal volume.
• These 122 phase nanoinclusions were found to be non-superconducting down to 2 K.
• No second magnetization peak was observed in magnetization measurements, unlike in CaKFe4As4.

Conclusions:

• The non-superconducting RbFe2As2 nanoinclusions in EuRbFe4As4 can function as effective two-dimensional pinning centers.
• These pinning centers may influence and potentially enhance the superconducting performance of the material.