Topological semimetals (TSMs), known for their topologically protected band crossings, give rise to a range of intriguing properties, including the anomalous Hall effect governed by Berry curvature in magnetic TSMs. Among these, cobalt-based magnetic TSMs, in particular, have been reported to exhibit the remarkable anomalous Hall response arising from the topologically nontrivial nodal line. In the present manuscript, we report the structural, magnetic, and magnetotransport properties of ${\mathrm{Co}}_2{\mathrm{VSn}}_{1-x}{\mathrm{Al}}_x$ ($x$ = 0, 0.25, 0.5, and 0.75), with the primary objective to experimentally understand the impact of nodal-line tuning near the Fermi level on intrinsic anomalous Hall conductivity (AHC). The tuning of nodal-line states is achieved by hole doping in ${\mathrm{Co}}_2\mathrm{VSn}$ through Al (three valence electrons) substitution at the Sn (four valence electrons) site. Our experimental results reveal that the magnitude of intrinsic AHC increases with Al doping up to $x$ = 0.5, from $\sim 148.3$ S/cm ($x$ = 0) to $\sim 203.2$ S/cm ($x$ = 0.5), showing a maximum enhancement of $\sim 40\%$ in magnitude relative to the undoped sample. Beyond this composition, a reduction in intrinsic AHC is observed. Our first-principles calculations confirm that ${\mathrm{Co}}_2\mathrm{VSn}$ hosts nodal line states, which gap out in the presence of spin-orbit coupling when the magnetization is considered along the [001] direction. Moreover, the obtained Bloch spectral function plots suggest that the nodal line gradually shifts toward the Fermi level with increasing Al substitution and nearly aligns with it for midcomposition. This results in the enhancement of total Berry curvature contribution near the Fermi level, leading to the maximum intrinsic AHC for $x$ = 0.5. Thus, the present experimental and theoretical results underscore the significance of nodal-line tuning near the Fermi level in enhancing the Berry curvature–driven AHC of the system, demonstrating a promising strategy to explore the interplay between magnetism and topological properties of the material.

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• Doping effects
• Electronic structure
• Hall effect
• Topological materials
• First-principles calculations