Tunable Magnetotransport across Competing Magnetic Phases in the Distorted Kagome Antiferromagnet HoPtSn

Abstract Competing magnetic phases in frustrated systems provide a fertile ground for unusual magnetic and electronic responses owing to their sensitivity to external perturbations. The distorted kagome antiferromagnet HoPtSn is an example of such a system, exhibiting successive magnetic transitions and multiple field-induced metamagnetic states at low temperatures. Here, we combine magnetic susceptibility, heat capacity, magnetotransport, and magnetization under hydrostatic pressure measurements on single crystals to investigate the interplay between the competing magnetic phases in HoPtSn. At ambient pressure, HoPtSn undergoes two magnetic transitions at TN1 ≈ 7.3 K and TN2 ≈ 2.7 K. The lower-temperature transition is accompanied by pronounced thermal and magnetic hysteresis, indicating its first-order character. Magnetization measurements reveal a series of field-induced transitions and a strongly anisotropic low-temperature phase diagram. Correspondingly, the magnetotransport exhibits sharp anomalies across the metamagnetic transitions together with clear field-history dependence, while Hall resistivity measurements reveal additional features that emerge within the ordered state. These results point to a strong coupling between electronic transport and magnetic reconstruction. Hydrostatic pressure leaves TN1 nearly unchanged, while it gradually shifts TN2 to higher temperatures, indicating that the competing magnetic phases respond differently to lattice compression, while the first-order transition remains robust throughout the investigated pressure range. Electronic structure calculations reveal several Dirac-like crossings near the Fermi level, suggesting possible interplay between these features and the complex magnetic phase space. Taken together, our results show that HoPtSn hosts a delicate balance between competing magnetic states, whose reconstruction leaves distinct signatures in the transport properties and can be continuously tuned by pressure. These findings highlight distorted kagome antiferromagnets as a promising platform for exploring the interplay between magnetic phase competition and electronic transport.