Oscillatory Spin Polarization and Magneto-Optic Kerr Effect in Fe3O4 Thin Films on GaAs(001)

TL;DR

This study investigates oscillatory spin polarization and magneto-optic effects in Fe3O4 thin films on GaAs(001), revealing quantum well states as the cause of thickness-dependent oscillations and sign reversals.

Contribution

It demonstrates the presence of oscillatory behavior in spin polarization and Kerr effect due to quantum well states in Fe3O4 thin films, a novel insight into spin-dependent phenomena.

Findings

Oscillations in FPP and MOKE with film thickness

Sign reversals of spin polarization and Kerr effect

Quantum well states explain the oscillatory behavior

Abstract

The spin dependent properties of epitaxial Fe3O4 thin films on GaAs(001) are studied by the ferromagnetic proximity polarization (FPP) effect and magneto-optic Kerr effect (MOKE). Both FPP and MOKE show oscillations with respect to Fe3O4 film thickness, and the oscillations are large enough to induce repeated sign reversals. We attribute the oscillatory behavior to spin-polarized quantum well states forming in the Fe3O4 film. Quantum confinement of the t2g states near the Fermi level provides an explanation for the similar thickness dependences of the FPP and MOKE oscillations.