Magnetism in rare-earth intermetallics is generally governed by the coupled evolution of $4f$ spin and orbital moments, which typically diminish together once long-range magnetic order vanishes. Here we show that PrGaSi provides a clear exception to this paradigm. The Pr-$4f$ orbital magnetic moment does not collapse with the spin moment; instead, x-ray magnetic circular dichroism measurements show that it remains robust and even increases in the paramagnetic regime. Such behavior reflects the strong localization of the $4f$ orbital moment, which recovers its intrinsic $4f^2$ character once spin order–induced quenching is lifted. PrGaSi is a noncentrosymmetric ternary compound in which Weyl-type itinerant electronic states are expected to emerge, and first-principles calculations reveal that these linear-dispersive carriers persist across spin-ordered and spin-disordered phases. Their robustness is intimately linked to a coherent, momentum-locked channel that coexists with long-range, anisotropic Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between localized Pr-$4f$ moments. Critical-scaling analysis provides evidence for long-range exchange interactions consistent with an RKKY-type mechanism associated with these itinerant electronic states. Furthermore, systematic magnetotransport measurements reveal an M-shaped magnetoresistance and low-temperature Hall anomalies, providing macroscopic evidence of the topological electronic responses coupled to this configuration. Together with the persistence of Weyl-type electronic features, the unusual decoupling between orbital strength and spin order positions PrGaSi as an unconventional magnetic system where localized orbital physics and itinerant topology remain intertwined across temperature regimes. These results highlight a scenario in which RKKY exchange coexists with Weyl-type itinerant electronic states, revealing a previously unexplored route for stabilizing orbital-anchored magnetism and for tuning magnetic anisotropy and topological responses in rare-earth systems.

Close

PrevNext

View figure in article

• Electronic structure
• Magnetic coupling
• Magnetic interactions
• Magnetic order
• RKKY interaction
• Antiferromagnets
• Crystal structures
• Magnetic systems
• Single crystal materials
• Weyl semimetal
• Angle-resolved photoemission spectroscopy
• Critical exponents
• Density functional theory
• First-principles calculations
• Magnetization measurements
• X-ray diffraction
• X-ray magnetic circular dichroism