In a groundbreaking study, researchers have achieved nanoscale imaging of altermagnetic states in manganese telluride (MnTe), marking a significant advancement in the field of spintronics. This innovative exploration of MnTe provides new insights into altermagnetism, a recently proposed magnetic state that combines characteristics of both ferromagnets and antiferromagnets, promising substantial improvements in data storage and processing technologies.
Altermagnetism is characterized by a time-reversal symmetry-breaking spin polarization without a net magnetization, a phenomenon that has eluded scientists for decades. The recent study conducted by a team of international scientists, including O.J. Amin and A. Dal Din, utilized advanced imaging techniques to map the altermagnetic order vector in MnTe at unprecedented scales. This mapping was achieved using X-ray magnetic circular dichroism (XMCD) and magnetic linear dichroism (XMLD) combined with photoemission electron microscopy, providing a detailed visualization of the magnetic textures within the material.
Manganese telluride, a prototypical altermagnetic material, was chosen for its unique magnetic properties. At temperatures below 310 K, MnTe exhibits a magnetic order within the crystal’s plane, making it an ideal candidate for this study. The researchers successfully mapped the altermagnetic order vector, revealing a rich landscape of magnetic textures from nanoscale vortices and domain walls to larger, micrometre-scale single-domain states.
The research team’s innovative approach allowed them to control the formation of these magnetic textures by utilizing the sensitivity of XMCD and XMLD to time-reversal symmetry breaking. This capability to visualize and manipulate altermagnetic states is expected to pave the way for new experimental studies in the field, exploring phenomena such as unconventional spin-polarization and the interplay of altermagnetism with superconducting and topological phases.
Furthermore, the study’s findings suggest that altermagnetism may solve the long-standing challenges in spintronics, particularly the limitations posed by the net magnetization in ferromagnets. Altermagnetic materials like MnTe offer the potential to combine the best of both ferromagnets and antiferromagnets, providing strong spin-current effects while maintaining high spatial, temporal, and energy scalability.
The implications of this research extend beyond fundamental science, with potential applications in developing highly scalable digital and neuromorphic spintronic devices. These devices could revolutionize how data is stored and processed, offering faster, more energy-efficient alternatives to current technologies.
The success of this study reflects the collaborative efforts of researchers across the globe, supported by institutions such as the University of Nottingham and the Royal Society. The work conducted at facilities like the MAX IV Laboratory in Sweden and Diamond Light Source in the UK played a crucial role in enabling the high-resolution imaging techniques necessary for this breakthrough.
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Reference
Amin, O.J., Dal Din, A., Golias, E. et al. Nanoscale imaging and control of altermagnetism in MnTe. Nature 636, 348–353 (2024). https://doi.org/10.1038/s41586-024-08234-x
