Unconventional magneto-transport properties of Co ₂ MnAl Heusler system under B ₂ disorder

Abstract Heusler alloys are highly regarded in the spintronics industry owing to their exceptional spin polarization properties. Nonetheless, their physical characteristics are significantly influenced by the degree of crystallographic order or disorder, which in turn substantially alters their electronic band structure, as well as their electronic and magnetic transport behaviors. Consequently, the interplay between the ordered and disordered structures in Heusler alloys is crucial for optimizing their performance in practical applications. In this context, we were compelled to systematically examine the influence of disorder on the physical properties of a well-recognized Heusler system, Co 2 MnAl. Two samples were prepared through the conventional arc-melting technique, and structural analysis based on x-ray diffraction patterns indicates that, despite both crystallizing in a B 2 -type disorder, they exhibit differing degrees of ordering. The B 2 disorder impacts magnetization and Curie temperature, while also inducing weak localization at low temperatures, which directly results in modified transport properties. Notably, the Co 2 MnAl sample with higher disorder demonstrates a larger half-metallic energy gap and increased anomalous Hall conductivity, attributable to the intrinsic contribution of enhanced Berry curvature hot spots near Weyl nodes.