Magnetism in the 2D Limit and Interface Superconductivity in Metal-Insulator La(2-x)Sr(x)CuO(4) Superlattices

TL;DR

This study investigates the magnetic properties of ultra-thin La(2)CuO(4) layers in superlattices, revealing antiferromagnetic order in thicker layers and a quantum-fluctuation-dominated magnetic state in thinner layers, coexisting near superconducting layers.

Contribution

It demonstrates the existence of a magnetic state in ultra-thin La(2)CuO(4) layers and its coexistence with superconductivity in a superlattice structure, using muon spin rotation measurements.

Findings

Antiferromagnetic order in layers thicker than 5 CuO(2) units.

Breakdown of long-range order and emergence of quantum-fluctuation-dominated magnetic state in thinner layers.

Magnetic state exists close to superconducting layers without transmitting supercurrents.

Abstract

We show, by means of low-energy muon spin rotation measurements, that few-unit-cells thick La(2)CuO(4) layers synthesized digitally by molecular beam epitaxy synthesis are antiferromagnetically ordered. Below a thickness of about 5 CuO(2) layers the long-range ordered state breaks down, and a magnetic state appears with enhanced quantum fluctuations and a reduced spin stiffness. This magnetic state can exist in close proximity (few Angstrom) to high-temperature superconducting layers, without transmitting supercurrents.