Superparamagnetic Reduced Graphene Oxide with Large Magnetoresistance: A Surface Modulation Strategy.

Area of Science:

• Spintronics
• Materials Science
• Condensed Matter Physics

Background:

• Graphene is explored for spintronics due to its unique electron magnetism and tunable properties.
• Achieving sensitive magnetoelectric response in graphene under ambient conditions remains a challenge.
• Current methods often require high magnetic fields and cryogenic temperatures.

Purpose of the Study:

• To develop a method for achieving sensitive magnetic field response in graphene-based materials at room temperature.
• To explore surface modulation as a strategy to induce superparamagnetism in reduced graphene oxide (rGO).
• To investigate the magnetoelectric properties of modified rGO for potential spintronic applications.

Main Methods:

• Surface modulation of reduced graphene oxide (rGO) via a mild oxidation process.
• Partial removal of covalently bound thiol groups from the carbon framework.
• Characterization of magnetic properties and magnetoresistance (MR) under low magnetic fields at room temperature.

Main Results:

• Successfully induced superparamagnetism in rGO through surface modulation.
• Observed a significant low-field negative magnetoresistance (MR) of -8.6% at 500 Oe and 300 K.
• Demonstrated sensitive magnetic field response under ambient conditions.

Conclusions:

• Surface modulation is an effective strategy to realize superparamagnetism in rGO.
• The developed method offers a new pathway for optimizing the magnetoelectric properties of two-dimensional materials.
• This work paves the way for practical spintronic devices operating at room temperature.