Asymmetric modification of the magnetic proximity effect in Pt/Co/Pt trilayers by the insertion of a Ta buffer layer

TL;DR

This study investigates how inserting a Ta buffer layer affects the magnetic proximity effect in Pt/Co/Pt trilayers, revealing that the buffer layer reduces the induced magnetism in Pt layers and offers a new control method for spin-transport applications.

Contribution

The paper demonstrates that a Ta buffer layer modifies the growth orientation of Pt and reduces the magnetic proximity effect, combining experimental and theoretical approaches for interface engineering.

Findings

Ta buffer layer decreases the induced magnetic moment in bottom Pt layer.

Ta buffer induces growth of Pt(011) instead of Pt(111).

Co induces more magnetic moment in Pt(111) than in Pt(011).

Abstract

The magnetic proximity effect in top and bottom Pt layers induced by Co in Ta/Pt/Co/Pt multilayers has been studied by interface sensitive, element specific x-ray resonant magnetic reflectivity. The asymmetry ratio for circularly polarized x-rays of left and right helicity has been measured at the Pt $L_3$ absorption edge (11567 eV) with an in-plane magnetic field ($\pm158$ mT) to verify its magnetic origin. The proximity-induced magnetic moment in the bottom Pt layer decreases with the thickness of the Ta buffer layer. Grazing incidence x-ray diffraction has been carried out to show that the Ta buffer layer induces the growth of Pt(011) rather than Pt(111) which in turn reduces the induced moment. A detailed density functional theory study shows that an adjacent Co layer induces more magnetic moment in Pt(111) than in Pt(011). The manipulation of the magnetism in Pt by the insertion of a Ta buffer layer provides a new way of controlling the magnetic proximity effect which is of huge importance in spin-transport experiments across similar kind of interfaces.