Antiferromagnetism in Ni-Based Superconductors.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity Research

Background:

• The parent compound NdNiO$_{2}$ shows no magnetic order at low temperatures.
• Superconductivity discovered in infinite-layer Nd$_{0.8}$ Sr$_{0.2}$ NiO$_{2}$ thin films (9-15 K) offers new avenues for studying superconductivity mechanisms.

Purpose of the Study:

• To synthesize superconducting Nd$_{0.8}$ Sr$_{0.2}$ NiO$_{2}$ thin films.
• To investigate the magnetic properties and their relation to superconductivity in these films.

Main Methods:

• Thin film synthesis of Nd$_{0.8}$ Sr$_{0.2}$ NiO$_{2}$ with varying thicknesses (8-40 nm).
• Measurement of exchange bias effect between superconducting films and ferromagnetic layers.
• X-ray magnetic linear dichroism (XMLD) measurements.

Main Results:

• Successful synthesis of superconducting Nd$_{0.8}$ Sr$_{0.2}$ NiO$_{2}$ thin films.
• Observation of a significant exchange bias effect, indicating antiferromagnetic order.
• Experimental confirmation of antiferromagnetic order using XMLD.

Conclusions:

• Antiferromagnetic order coexists with superconductivity in Nd$_{0.8}$ Sr$_{0.2}$ NiO$_{2}$ thin films.
• These findings are crucial for understanding the underlying mechanisms of this novel form of superconductivity.