Spintronic Device Technologies and Magnetic Tunnel Junctions

Spintronic devices exploit the electron’s spin in addition to its charge, offering non-volatile operation, enhanced data throughput and reduced energy consumption. Central to this field are magnetic tunnel junctions (MTJs), in which two ferromagnetic layers are separated by an ultra-thin insulating barrier. The relative orientation of the layer magnetisations controls the tunnelling resistance, a phenomenon known as tunnel magnetoresistance (TMR). Advances in materials engineering—ranging from crystalline MgO barriers to two-dimensional insulators such as hexagonal boron nitride and transition metal dichalcogenides—have driven TMR values above 200 % at room temperature. Control of magnetic anisotropy, Gilbert damping and interfacial exchange coupling underpins reliable switching in magnetic random access memory (MRAM) elements and spin-torque oscillators. Emerging architectures harness spin–orbit torques and proximity effects at hybrid interfaces to achieve deterministic, low-current manipulation of magnetisation. Concurrent progress in spin injection and detection in semiconducting channels, including multilayer molybdenum disulfide, opens pathways to integrate logic and memory at the nanoscale. These developments collectively position spintronic technologies as a transformative platform for next-generation data storage, sensing and computing applications.

Research from Nature Portfolio

State-of-the-art epitaxial graphene-based MTJs have demonstrated magnetoresistance signals exceeding 80 %, highlighting the crucial role of hybridisation and proximity at the ferromagnet–graphene interface in tailoring spin-dependent density of states. Investigations of spin injection into multilayer molybdenum disulfide channels have achieved two-terminal magnetoresistance near 1 % over several hundred nanometres, revealing suppressed spin-relaxation and long diffusion lengths when interfaces balance resistances effectively. Detailed studies of CoFeB/MgO nanodots have shown that magnetic reversal is dominated by thermally nucleated incoherent switching, establishing intrinsic limits to reliability at sub-30 nm dimensions and clarifying the thermal switching-field distribution relevant to high-density MRAM scaling.

Spintronic Device Technologies and Magnetic Tunnel Junctions publication trend

The graph below shows the total number of articles in spintronic device technologies and magnetic tunnel junctions across all publications each year (not limited to Nature Index journals).

Technical terms

Spintronics: A field exploiting electron spin and charge for information processing and storage.

Magnetic tunnel junction (MTJ): A nanoscale structure of two ferromagnets separated by an insulating barrier through which electrons quantum-tunnel.

Tunnel magnetoresistance (TMR): The change in electrical resistance of an MTJ depending on the relative magnetisation alignment of its ferromagnetic layers.

Spin polarisation: The imbalance of spin-up and spin-down electron populations contributing to a net spin current.

Magnetic anisotropy: The directional dependence of a material’s magnetic energy, dictating preferred axes for magnetisation.

Dzyaloshinskii–Moriya interaction (DMI): An antisymmetric exchange coupling that favours canted spin arrangements and chiral magnetic textures.

References

1. Magnetoresistance of vertical Co-graphene-NiFe junctions controlled by charge transfer and proximity-induced spin splitting in graphene. 2D Materials (2017).
2. Electrical spin injection and detection in molybdenum disulfide multilayer channel. Nature Communications (2017).
3. Thermally nucleated magnetic reversal in CoFeB/MgO nanodots. Scientific Reports (2017).
4. Temperature-dependent properties of CoFeB/MgO thin films: Experiments versus simulations. Physical Review B (2018).
5. 2D-MTJs: introducing 2D materials in magnetic tunnel junctions. Journal of Physics D (2017).
6. Disruptive effect of Dzyaloshinskii-Moriya interaction on the magnetic memory cell performance. Applied Physics Letters (2016).