Growth mode, magnetic and magneto-optical properties of pulsed-laser-deposited Au/Co/Au(111) trilayers

TL;DR

This study investigates the growth, magnetic, and magneto-optical properties of Au/Co/Au(111) trilayers grown by pulsed-laser deposition, revealing room-temperature ferromagnetism despite interfacial intermixing and characterizing their magnetic anisotropy and MO response.

Contribution

It demonstrates that pulsed-laser deposition induces interfacial intermixing yet still produces ferromagnetic ultrathin trilayers with unique magnetic and MO properties.

Findings

Room-temperature ferromagnetism at 1 atomic layer Co coverage

Perpendicular magnetic anisotropy with reduced anisotropy constants

Linear magneto-optical response with Co thickness above 3 atomic layers

Abstract

The growth mode, magnetic and magneto-optical properties of epitaxial Au/Co/Au(111) ultrathin trilayers grown by pulsed-laser deposition (PLD) under ultra-high vacuum are presented. Sapphire wafers buffered with a single-crystalline Mo(110) bilayer were used as substrates. Owing to PLD-induced interfacial intermixing at the lower Co/Au(111) interface, a layer-by-layer growth mode is promoted. Surprisingly, despite this intermixing, ferromagnetic behavior is found at room temperature for coverings starting at 1 atomic layer (AL). The films display perpendicular magnetization with anisotropy constants reduced by 50% compared to TD-grown or electrodeposited films, and with a coercivity more than one order of magnitude lower ($\lesssim$ 5 mT). The magneto-optical (MO) response in the low Co thickness range is dominated by Au/Co interface contributions. For thicknesses starting at 3 AL Co, the MO response has a linear dependence with the Co thickness, indicative of a continuous-film-like MO behavior.