Magnetoresistive Sensing Techniques in Graphene-Based Devices

Graphene’s atomic thickness and exceptional carrier mobility have driven extensive research into its use for magnetoresistive sensing. Techniques exploit changes in electrical resistance under an applied magnetic field, primarily via the Hall effect and extraordinary magnetoresistance (EMR) in hybrid structures. In Hall sensors, graphene’s low residual carrier density and ambipolar transport enable high sensitivity and frequency-tunable operation; encapsulation in hexagonal boron nitride further enhances stability and noise performance. EMR devices combine graphene with a high-conductivity metal to redirect current paths under magnetic bias, yielding resistance changes of orders of magnitude. Advances in substrate engineering, contact modification and scalable chemical vapour deposition have addressed long-standing challenges in contact resistance, flicker noise and environmental degradation. Nanoscale fabrication has pushed spatial resolution to sub-100 nm, while flexible substrates and p–n junction architectures open new application realms for wearable and tunable sensors. Collectively, these developments point towards ultralow limits of detection, broad operational bandwidths and integration into biomagnetic imaging, non-destructive testing and autonomous navigation systems.

Research from Nature Portfolio

Recent studies have demonstrated that electrostatic modification of the underlying oxide substrate can form large-area graphene p–n junctions in a single device. The technique uses controlled electrical stress to locally perturb the SiO₂ potential, creating adjacent p-type and n-type regions within a Hall bar. This architecture exhibits distinctly different Hall responses and enhanced longitudinal magnetoresistance in the gated regions, suggesting a platform for spatially reconfigurable magnetic sensors.

Ultraclean graphene devices encapsulated between hexagonal boron nitride and graphite contacts have been shown to achieve record-low magnetic field detection limits. At ambient temperature and 1 kHz bandwidth, detection thresholds approach 700 nT Hz⁻¹ᐟ², while cryogenic operation yields sensitivities around 80 nT Hz⁻¹ᐟ². In fields up to several tesla, these devices maintain performance in the quantum Hall regime, underlining graphene’s versatility for both fundamental research and high-field sensing applications.

Magnetoresistive Sensing Techniques in Graphene-Based Devices publication trend

The graph below shows the total number of articles in magnetoresistive sensing techniques in graphene-based devices across all publications each year (not limited to Nature Index journals).

Technical terms

Magnetoresistance: Change in electrical resistance when a material is subjected to a magnetic field.

Hall effect: Generation of a transverse voltage in a conductor carrying current under a perpendicular magnetic field.

Extraordinary magnetoresistance (EMR): Large geometric magnetoresistance in hybrid structures combining high-mobility and high-conductivity materials.

Flicker noise: Low-frequency electrical noise with power spectral density inversely proportional to frequency, often limiting sensor resolution.

Limit of detection (LOD): Minimum magnetic field strength that a sensor can reliably discern above its noise floor.

References

1. Minimizing Contact Resistance and Flicker Noise in Micro Graphene Hall Sensors Using Persistent Carbene Modified Gold Electrodes. ACS Applied Materials & Interfaces (2024).
2. Highly Sensitive Hall Sensors Based on Chemical Vapor Deposition Graphene. ACS Applied Nano Materials (2023).
3. Study of graphene p-n junctions formed by the electrostatic modification of the SiO2 substrate. Scientific Reports (2024).
4. Universal material trends in extraordinary magnetoresistive devices. Journal of Physics Materials (2023).
5. Magnetic field detection limits for ultraclean graphene Hall sensors. Nature Communications (2020).
6. Hall sensors batch-fabricated on all-CVD h-BN/graphene/h-BN heterostructures. Scientific Reports (2017).
7. Gate-tunable graphene-based Hall sensors on flexible substrates with increased sensitivity. Scientific Reports (2019).
8. Nanoscale graphene Hall sensors for high-resolution ambient magnetic imaging. Scientific Reports (2019).
9. Operation of graphene magnetic field sensors near the charge neutrality point. Communications Physics (2019).