Ubiquitous long-range antiferromagnetic coupling across the interface between superconducting and ferromagnetic...

Area of Science:

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

Background:

• The proximity effect describes competition between magnetism and superconductivity across interfaces.
• It's well-understood in conventional superconductors and metallic ferromagnets.
• Less is known about this effect in high-critical-temperature oxide materials.

Purpose of the Study:

• Investigate the proximity effect in cuprate/manganite heterostructures.
• Understand the mechanism of weak ferromagnetism at the interface.
• Determine the impact on superconductivity, specifically critical temperature.

Main Methods:

• Fabrication of superconducting La(1.85)Sr(0.15)CuO(4) thin films.
• Coupling with the ferromagnet La(0.66)Sr(0.33)MnO(3).
• Theoretical modeling of heterostructures.

Main Results:

• Weak ferromagnetism observed in interfacial CuO2 planes of the superconductor.
• Ferromagnetism arises from spin-polarized electron charge transfer, even without direct covalent bonding.
• Theoretical modeling confirms this is a general effect in cuprate/manganite systems.

Conclusions:

• The Dzyaloshinskii-Moriya interaction mediates magnetization propagation from the interface.
• This interfacial magnetism depresses the critical temperature of the superconductor.
• The findings offer insights into controlling superconductivity in oxide heterostructures.