Tailoring Antiferromagnetic Orders and Spin Transport in Noncollinear Mn3Pt Multilayers

Noncollinear antiferromagnetic (NCAF) materials, such as Mn₃Pt, exhibit remarkable spin-orbit and tunneling phenomena, positioning them as promising candidates for low-power, stray-field immune nanoelectronics. However, precise control of AF order and spin transport properties, and understanding of their physical mechanisms, remains challenging. In this work, the interplay between crystal structure, magnetic orders, and anomalous Hall effect (AHE) is established in single-crystalline Mn₃Pt (001) synthesized from a [Mn/Pt]₂₀ multilayers with tunable Mn layer thickness (t_Mn). Resonant elastic X-ray scattering reveals a magnetic order transition at T_c≈240 K for the sample with t_Mn = 0.7 nm, which notably coincides with an AHE polarity reversal at ≈230 K. Importantly, we demonstrate that T_c can be precisely engineered by fine-tuning t_Mn to modulate lattice constant and spin canting. Further, first-principles calculations affirm the lattice parameter and spin canting dependence of AHE from the ground-state Γ₁₀ magnetic symmetry. Finally, a refined analytical model is introduced to elucidate the intrinsic and extrinsic AHE contributions in NCAF material comprising hybrid magnetic orders. These findings provide a robust framework for tailoring transport properties toward the realization of next-generation AF computing technologies.