Interfacial Modulation on Co_0.2Fe_2.8O₄ Epitaxial Thin Films for Anomalous Hall Sensor Applications

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Magnetic oxide films exhibit a strong anomalous Hall effect (AHE), crucial for magnetic sensor applications due to high sensitivity and polarization.
• Improving the linearity of anomalous Hall sensors is essential for enhanced device performance and accuracy.

Purpose of the Study:

• To investigate the use of interface regulation to enhance the linearity of the anomalous Hall effect (AHE) in magnetic oxide films.
• To explore the impact of inserting a graphene layer on the structural and electrical properties of Co_0.2Fe_2.8O₄ (CoFeO) thin films.

Main Methods:

• Growth of spinel ferrite CoFeO thin films on MgAl₂O₄ (MAO) substrates.
• Interfacial modification by inserting a graphene layer between the MAO substrate and the CoFeO film.
• Detailed structural analysis (e.g., epitaxy, nanostructure) and electrical testing (Hall resistance measurements).

Main Results:

• Graphene insertion maintained the epitaxial nature of CoFeO films while inducing a nanopillar-like nanostructure.
• The graphene-inserted heterostructure demonstrated high sensitivity and linearity of the Hall resistance signal with respect to the magnetic field.
• Reduced hysteresis and improved linearity of the anomalous Hall resistance were observed in the graphene-modified films.

Conclusions:

• Interface engineering via graphene insertion is an effective strategy to enhance the linearity of anomalous Hall effect sensors.
• The observed improvements are attributed to changes in nanostructure and potential interfacial coupling effects.
• This approach offers a promising pathway for tuning ferrite thin film properties for advanced sensor applications.