X-Type Antiferromagnets Show 90% Efficient Spin Conversion
Unique Fermi Surface Geometry Allows X-type Antiferromagnets to Convert Charge-Spin 90% Efficiently Antiferromagnetic materials, which could power next-generation spintronics, have long been studied for superior charge current-to-spin current conversion. An important discovery was made by Hubei Polytechnic University researchers Wancheng Zhang, Yong Liu, and Jiabin Wang, and Wuhan University colleagues. A recently discovered class of antiferromagnets called “X-type” has a particularly effective mechanism.
This research suggests that X-type antiferromagnets could be used to make low-power spintronic devices that process information by altering spin rather than charge. These materials produce high spin currents better than other antiferromagnetic systems and regular ferromagnets. Spin Conversion Efficiency Improves with X-type Stacking The study advances spintronics with its exceptional charge-to-spin conversion efficiency in the antiferromagnet β-Fe₂PO₅. Due to its high inherent charge-to-spin conversion, this material outperforms many others. High efficiency, reaching 90% charge-to-spin conversion efficiency, is due to the unique X-type stacking of the cross-chain antiferromagnetic structure. The electrical structure's Fermi surface shape and non-coplanar spin pattern are unique to this structure. This geometry is crucial because it maintains zero net magnetisation and improves spin splitting. T-odd spin currents can be efficiently created with the particular electrical structure. A spin qubit conductivity tensor symmetry investigation reveals the fundamentals of this potent spin current generation. Importantly, the material possesses strong T-odd spin Hall conductivity, so charge and spin current are directly connected. This direct link maximises essential spin-orbit torque conversion efficiency. The team accurately predicted the materials' behaviour, showing that X-type antiferromagnets can be very efficient spin generators. These new X-type antiferromagnetic materials were researched to improve spin current production, a key component of next-generation spintronic devices, outperforming existing systems and altermagnets. The team's superior theoretical computations modelled these materials' electrical structure to accurately characterise electron behaviour and magnetic order. These simulations incorporated spin-orbit coupling effects, which are essential to understanding spin current creation. Team demonstrated a significant performance advantage with β-Fe₂PO₅ compared to other materials. The spin currents of X-type antiferromagnets are superior to those of altermagnets in some directions. The materials generate spin currents that outperform altermagnets. The reported events are linked to altermagnetism, where symmetry characteristics and non-coplanar spin textures promote charge-to-spin conversion and spin-orbit coupling. Comprehensive measurements and analysis validate this exceptional performance. Comparative analysis demonstrates that the Hall angle exceeds all known material systems and that the predicted spin Hall conductivity has a high conversion efficiency. Memory and logic device control A major advantage of X-type antiferromagnets is their spin current control. Experiments indicate that spin current polarisation is directly controlled by el vector orientation. This direct contact lets researchers control spin flow. The team demonstrated that accurate Néel vector orientation can influence spin current polarisation. This allows out-of-plane spin-polarized current generation. Later research confirmed the creation of out-of-plane spin currents with 80% conversion efficiency, a major improvement over current materials. These findings suggest that X-type antiferromagnets can be used to make low-power spintronic devices due to their novel and efficient spin current source. This discovery opens up several possibilities for quicker, more energy-efficient spin-orbit torque-based memory and logic devices. Its knowledge into high charge-to-spin conversion efficiency materials will drive future materials discovery. The group emphasises crystal orientation management during material production to maximise charge-to-spin conversion. We conclude that X-type antiferromagnets provide a flexible and highly adjustable spin source platform and offer a design strategy for next-generation spintronic devices.
