Driving noncollinear interlayer exchange coupling intrinsically in magnetic trilayers

TL;DR

This paper demonstrates that by tuning the spacer width in Fe/Ag/Fe trilayers, one can intrinsically induce noncollinear magnetic alignment mediated by quantum well states, advancing spintronic device control.

Contribution

The study provides a theoretical framework showing how spacer width manipulation leads to noncollinear IEC in magnetic trilayers, supported by analytic and first-principles calculations.

Findings

Spacer width significantly influences IEC and magnetic alignment.

At specific spacer widths, magnetic moments become perpendicular.

Quantum well states mediate noncollinear spin spirals.

Abstract

Ferromagnetic side layers sandwiching a nonmagnetic spacer as a metallic trilayer has become a pivotal platform for achieving spintronic devices. Recent experiments demonstrate that manipulating the width or the nature of conducting spacer induces noncollinear magnetic alignment between the side layers. Our theoretical analysis reveals that altering the width of spacer significantly affects the interlayer exchange coupling (IEC), resulting in noncollinear alignment. Through analytic and first-principles methods, our study on the Fe/Ag/Fe trilayer shows that at a specific width of the Ag spacer, the magnetic moments of side layers tend to be perpendicular. This alignment is mediated by Ag quantum well states, exhibiting spin spirals across the trilayer. Our results reveal that the noncollinear IEC offers a degree of freedom to control magnetic devices and boot spintronic technology with improved transport capabilities.