Magnetoresistive Sensor Technologies and Applications

Magnetoresistive sensors exploit changes in electrical resistance in response to external magnetic fields, offering high sensitivity, rapid response times and scalability. Principal variants include anisotropic magnetoresistance (AMR), giant magnetoresistance (GMR) and tunnelling magnetoresistance (TMR), each distinguished by the underlying spin-dependent scattering or tunnelling effects within thin-film or multilayer structures. Spintronic architectures using magnetic tunnel junctions enable compact, low-power devices with sub-picotesla detectivity and minimal noise, especially when combined with magnetic flux concentrators and bridge configurations. These sensors underpin a broad spectrum of applications, from non-destructive testing of infrastructure and industrial process control to precision electrical current measurement in smart grids. In the biomedical arena, magnetoresistive technologies facilitate wearable and implantable devices for magnetocardiography, magnetoencephalography and emerging magnetomyography systems, delivering room-temperature, high-resolution detection of bio-magnetic signals. Recent advances further extend use cases to geophysical surveying, navigation and space research, where mass, volume and power constraints demand extreme miniaturisation. The ongoing convergence of nanofabrication, materials engineering and integrated circuit design continues to drive enhanced performance, opening pathways to portable, contactless diagnostics and ubiquitous Internet of Things sensing networks.

Research from Nature Portfolio

One study introduced biocompatible giant magnetoresistance micro-probes capable of recording local magnetic fields from action potentials in vitro, demonstrating that sensitivity remains nearly size independent and enabling miniaturisation for in vivo magnetophysiology. Another report described scalp-attached tunnelling magnetoresistance sensors achieving sub-millimetre separation from the head, using magnetic flux concentrators to enhance sensitivity. This single-channel system captured the N20m component of somatosensory evoked responses at a 2.6 mm sensor–scalp distance, illustrating a new approach to non-invasive brain imaging with millimetre and millisecond resolution.

Magnetoresistive Sensor Technologies and Applications publication trend

The graph below shows the total number of articles in magnetoresistive sensor technologies and applications across all publications each year (not limited to Nature Index journals).

Technical terms

Magnetoresistance: Variation of electrical resistance in a material under an external magnetic field.

Anisotropic magnetoresistance (AMR): Magnetoresistance arising from spin–orbit coupling within a single ferromagnetic layer, dependent on the angle between current and magnetisation.

Giant magnetoresistance (GMR): Large magnetoresistive effect observed in multilayer structures of alternating ferromagnetic and non-magnetic conductive layers.

Tunnelling magnetoresistance (TMR): Resistance change due to spin-polarised electron tunnelling across an insulating barrier between ferromagnetic electrodes.

Magnetic tunnel junction (MTJ): Nanoscale device consisting of two ferromagnetic layers separated by an ultrathin insulating barrier, forming the basis of TMR sensors.

Magnetic flux concentrator: Soft magnetic structure that amplifies weak external fields by guiding and concentrating magnetic flux into the sensing element.

Detectivity: Figure of merit representing the smallest magnetic field amplitude a sensor can reliably measure per unit bandwidth.

References

1. Magnetocardiography and magnetoencephalography measurements at room temperature using tunnel magneto-resistance sensors. Applied Physics Express (2018).
2. Local recording of biological magnetic fields using Giant Magneto Resistance-based micro-probes. Scientific Reports (2016).
3. Scalp attached tangential magnetoencephalography using tunnel magneto-resistive sensors. Scientific Reports (2022).
4. Sub-pT magnetic field detection by tunnel magneto-resistive sensors. Applied Physics Express (2021).
5. Serial MTJ-Based TMR Sensors in Bridge Configuration for Detection of Fractured Steel Bar in Magnetic Flux Leakage Testing. Sensors (2021).
6. High Sensitivity Differential Giant Magnetoresistance (GMR) Based Sensor for Non-Contacting DC/AC Current Measurement. Sensors (2020).
7. Miniaturized Magnetic Sensors for Implantable Magnetomyography. Advanced Materials Technologies (2020).