Abstract Rare-earth-free Mn-based binary alloy L10-MnAl with bulk perpendicular magnetic anisotropy (PMA) holds promise for high-performance magnetic random-access memory (MRAM) devices driven by spin-orbit torque (SOT). However, the lattice-mismatch issue makes it challenging to place the conventional spin current sources, such as heavy metals, between the L10-MnAl layer and substrate. In this work, we propose a solution by using the B2-CoGa alloy as the spin current source. The lattice-matching enables high-quality epitaxial growth of 2-nm-thick L10-MnAl on B2-CoGa, and the L10-MnAl exhibits a large PMA constant of 1.04×106 J/m3. Subsequently, the considerable spin Hall effect in B2-CoGa enables the achievement of SOT-induced deterministic magnetization switching. Moreover, we have quantitatively determined the SOT efficiency in the bilayer. Furthermore, we have designed an L10-MnAl/B2-CoGa/Co2MnGa structure to achieve field-free magnetic switching. Our results offer valuable insights for achieving high-performance SOT-MRAM devices based on L10-MnAl alloy