Static Magnetic Proximity Effect in Pt Layers on Sputter-Deposited NiFe2O4 and on Fe of Various Thicknesses Investigated by XRMR

TL;DR

This study investigates the magnetic proximity effect in Pt layers on sputter-deposited NiFe2O4 and Fe, finding no significant proximity-induced magnetization in Pt, and clarifying the interface dependence of the effect.

Contribution

It provides the first detailed comparison of magnetic proximity effects in sputter-deposited versus chemically deposited NiFe2O4 films using XRMR.

Findings

No magnetic response detected in Pt down to 0.04 μB per atom.

Proximity effect depends on interface properties of the magnetic material.

Sputter-deposited films show similar proximity effects to chemically deposited ones.

Abstract

The longitudinal spin Seebeck effect is detected in sputter-deposited NiFe2O4 films using Pt as a spin detector and compared to previously investigated NiFe2O4 films prepared by chemical vapor deposition. Anomalous Nernst effects induced by the magnetic proximity effect in Pt can be excluded for the sputter-deposited NiFe2O4 films down to a certain limit, since x-ray resonant magnetic reflectivity measurements show no magnetic response down to a limit of 0.04 {\mu}B per Pt atom comparable to the case of the chemicallydeposited NiFe2O4 films. These differently prepared films have various thicknesses. Therefore, we further studied Pt/Fe reference samples with various Fe thicknesses and could confirm that the magnetic proximity effect is only induced by the interface properties of the magnetic material.