In a groundbreaking advancement in the field of condensed matter physics, scientists have uncovered an extraordinary phenomenon within antiferromagnetic kagome semimetal heterostructures that challenges established understandings of magnetoresistance behavior. The multidisciplinary team from the High Magnetic Field Laboratory (CHMFL) under the Hefei Institutes of Physical Science, Chinese Academy of Sciences, alongside collaborators from the State Key Laboratory of Semiconductor Physics and Chip Technologies at the Institute of Semiconductors, CAS, have reported the observation of anomalous oscillatory magnetoresistance. This discovery not only sheds light on intricate magnetic interactions in novel materials but also opens new horizons for the design of next-generation topological spintronic devices.
At the core of this research lies the unique class of materials known as antiferromagnetic kagome semimetals. These materials exhibit a highly frustrated lattice geometry named after the traditional Japanese kagome basket-weaving pattern, resulting in a web of interlinked triangles. This topology induces complex interactions among electron spins, fostering an environment where geometric frustration and strong spin correlations interface with the electronic band topology. Such interplay in the kagome lattice has driven considerable interest, as it allows the stabilization of exotic quantum phases and excitations, making these materials prime candidates for future antiferromagnetic spintronics applications.
The research team synthesized heterostructures combining FeSn, an antiferromagnetic kagome semimetal, with a Pt (platinum) layer. This interface engineering is pivotal because it intentionally breaks inversion symmetry, which plays a fundamental role in allowing Dzyaloshinskii–Moriya interactions (DMI) to emerge. DMI is an antisymmetric exchange interaction known to stabilize chiral spin textures such as skyrmions and spin spirals, features that are otherwise prohibited in centrosymmetric environments. By precisely controlling the thickness of the FeSn layer and the resulting interface characteristics, the researchers demonstrated the ability to tune the strength of the DMI, thereby manipulating the spin configurations within the FeSn itself.
Magnetotransport measurements revealed an unconventional magnetoresistance response that deviates starkly from the well-understood Shubnikov–de Haas oscillations commonly associated with Landau quantization in high magnetic fields. In these FeSn/Pt heterostructures, the team observed damped oscillatory magnetoresistance within low magnetic fields, indicating a fundamentally different underlying mechanism. This magnetoresistance behavior presents as oscillations in electrical resistance when subjected to varying magnetic fields but cannot be accounted for by known classical or quantum oscillatory transport phenomena.
To elucidate the microscopic origins of these anomalous transport properties, the researchers employed magnetic force microscopy (MFM) under extreme conditions—a home-built system capable of operating at low temperatures and subjected to intense magnetic fields via the Steady High Magnetic Field Facility (SHMFF). Through direct real-space visualization, the MFM imaging unveiled a variety of topological spin textures at the FeSn/Pt interface. These topological magnetic structures—essentially localized, stable configurations of spin arrangements distinguished by their nontrivial spatial topology—offer compelling evidence that the anomalous magnetoresistance stems from magnetoelectric coupling induced by these spin textures.
The identification of these previously elusive antiferromagnetic topological spin textures represents a monumental milestone, as such textures are notoriously difficult to detect and manipulate compared to their ferromagnetic counterparts. Their presence signifies that topological protection and intricately intertwined spin states are achievable in antiferromagnetic materials, amplifying their potential utility in spintronic devices where low-energy dissipation and high-frequency operation are paramount.
Beyond merely documenting the discovery, this study provides vital insights into the complex interplay between geometric frustration, spin interactions, and band topology in the emergence of topological spin structures. The ability to control these textures through interfacial engineering and DMI tuning introduces a versatile platform for designing future devices that exploit robust topological states. This could revolutionize applications ranging from ultra-dense memory storage to quantum computation elements, where information encoding via spin configurations offers enhanced speed and efficiency.
Moreover, the observed magnetoresistance oscillations linked with topological spin states present a new diagnostic avenue for investigating the dynamic nature of antiferromagnetic spin textures. Conventional techniques often fall short in discerning such subtle magnetic phenomena, making the combination of precision heterostructure fabrication and advanced microscopy instrumental to advancing the field.
This investigation also underscores the significance of low-field magnetic regimes, which are more practical for technological applications compared to extreme magnetic conditions often required for observing quantum effects. Harnessing low-field topological magnetoresistance responses could pave the way for implementing these phenomena in commercial devices without necessitating high operational power or specialized infrastructure.
The successful integration of FeSn and Pt layers encourages exploration into other heterostructure combinations and material interfaces to broaden the spectrum of tunable topological magnetic phases. As the understanding of such systems deepens, it may lead to the discovery of novel quantum behaviors and unprecedented functionalities within antiferromagnetic spintronics.
In summary, the discovery of anomalous magnetoresistance oscillations tied unequivocally to topological magnetic textures in antiferromagnetic kagome semimetal heterostructures represents a transformative advancement bridging fundamental physics with applied material science. By revealing how interface-induced Dzyaloshinskii–Moriya interactions engineer complex spin textures manifesting in unique transport signatures, this work fundamentally enriches the toolbox for quantum materials research and spintronic innovation.
As the field moves forward, the implications of this breakthrough could ripple across multiple domains, including information technology, sensing, and quantum devices, heralding a new era where antiferromagnetic topological spintronic devices become not just theoretical constructs but tangible technological realities.
Subject of Research: Anomalous magnetoresistance and topological spin textures in antiferromagnetic kagome semimetal heterostructures
Article Title: Anomalous Magnetoresistance in an Antiferromagnetic Kagome Semimetal Heterostructures
News Publication Date: 29-Nov-2025
Web References:
https://doi.org/10.1002/adfm.202519240
Image Credits: FENG Qiyuan
Keywords
Physical sciences
