Henkel analysis of Fe/Er multilayers prepared by electron-beam evaporation

Abstract

Fe/Er multilayers were prepared by high-vacuum electron-beam evaporation system and their microstructures have been investigated. Henkel analysis was performed via isothermal remanent magnetization curve and direct current demagnetization curve. Magnetic measurement indicates that Fe/Er multilayers have an easy axis in film plane and a small value of positive magnetoresistance. It is showed that the Er layer will change to an amorphous structure when its thickness is below 3.5 nm. Hence, Δm plots were established according to Henkel analysis data. The results show that Δm plot has a strong dependence on the thickness of Fe and Er layers. When the thickness of Fe layer remained unchanged, Δm plot indicated that the magnetic coupling was oscillating with the layer thickness; and when the thickness of Er layer was 8.8 nm, Δm plot showed a positive-negative overturn of magnetic interaction, which revealed the interplay between the demagnetization and exchange coupling effect in multilayer. The explanation of Δm plot was also discussed via a simplified model, i.e., a competition between demagnetizing interaction and magnetizing interaction.