Cohesive properties of PbBi/Fe₃O₄ and PbBi/(Fe,Cr)₃O₄ interfaces

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Understanding oxide interfaces is crucial for materials performance.
• Lead bismuth (PbBi) interaction with oxides like Fe3O4 and (Fe,Cr)3O4 is not fully characterized.
• First principles calculations offer insights into interfacial phenomena.

Purpose of the Study:

• To investigate the impact of PbBi on the cohesive properties of Fe3O4 and (Fe,Cr)3O4 interfaces.
• To determine the role of oxygen and chromium content in interface stability.
• To elucidate the energetic favorability of different interface terminations.

Main Methods:

• First principles calculations were employed to model PbBi/oxide interfaces.
• Analysis of cohesive strength, bond-dissociation energies, and electronic structures.
• Comparison of various interface terminations (e.g., Pb-O, Bi-O, Bi-Cr, Bi-Fe).

Main Results:

• PbBi addition reduces the cohesive strength of Fe3O4 and (Fe,Cr)3O4 interfaces.
• Oxygen and chromium content significantly affect interface properties, particularly under low oxygen conditions.
• Pb-O terminated interfaces are energetically favorable and more stable than Bi-O terminated ones.
• Bi-Cr and Bi-Fe interfaces show higher stability than Pb-Cr and Pb-Fe interfaces.
• Interface stability decreases with insufficient oxygen or low PbBi wetting, with PbBi/Fe3O4 being more sensitive.

Conclusions:

• PbBi significantly alters the cohesive properties and stability of Fe3O4 and (Fe,Cr)3O4 interfaces.
• Oxygen stoichiometry and chromium content are critical factors governing interface behavior.
• Energetic favorability dictates the preferred interface termination, influencing overall stability.
• The findings provide a fundamental understanding of PbBi-oxide interactions, aligning with experimental observations.