MgO thickness-induced spin reorientation transition in Co0.9Fe0.1/MgO/Co0.9Fe0.1 structure

TL;DR

This study investigates how varying MgO thickness influences magnetic anisotropy in a layered heterostructure, revealing a spin reorientation transition at around 0.8 nm due to interlayer exchange coupling.

Contribution

It demonstrates the thickness-dependent spin reorientation transition in CoFe/MgO/CoFe structures, highlighting the role of interlayer exchange coupling in magnetic anisotropy evolution.

Findings

Spin reorientation occurs at MgO thickness of about 0.8 nm.

Magnetic anisotropy constants were quantified using ferromagnetic resonance.

Interlayer exchange coupling influences the magnetic anisotropy transition.

Abstract

The magnetic anisotropy (MA) of Mo/Au/Co0.9Fe0.1/Au/MgO(0.7 - 3 nm)/Au/Co0.9Fe0.1/Au heterostructure has been investigated at room temperature as a function of MgO layer thickness (tMgO). Our studies show that while the MA of the top layer does not change its character upon variation of tMgO, the uniaxial out-of-plane MA of the bottom one undergoes a spin reorientation transition at tMgO of about 0.8 nm, switching to the regime where the coexistence of in- and out-of-plane magnetization alignments is observed. The magnitudes of the magnetic anisotropy constants have been determined from ferromagnetic resonance and dc-magnetometry measurements. The origin of MA evolution has been attributed to a presence of an interlayer exchange coupling (IEC) between Co0.9Fe0.1 layers through the thin MgO film.