Perpendicular magnetic anisotropy and electrical transport properties of as-deposited Pt/Co₂MnSi_n multilayers

In pursuit of ultra-high-density and stable data storage devices, film materials with perpendicular magnetic anisotropy (PMA) are highly desirable. The exploitation of interfacial effects to induce PMA in heavy metal/ferromagnetic multilayers has become a major research focus. In this study, the PMA and electrical transport properties of Ta (6 nm)/Pt (2 nm)/Co_2MnSi (t_\rm CMS nm)_n/Pt (4 nm) multilayers in the as-deposited state were systematically investigated, with particular focus on the effects of ferromagnetic layer thickness (t_\rm CMS = 0.50 nm-1.50 nm) and the number of periods (n = 1-8). All samples were fabricated by magnetron sputtering and were not subjected to any annealing process. The magnetic results show that the multilayers exhibit PMA when the Co_2MnSi thickness t_\rm CMS \le 1.00 nm. Notably, an effective magnetic anisotropy constant K_\rm eff = 1.90\times 10^6 erg/cm^3 (1 erg = 10^-7 J) is achieved for the sample with t_\rm CMS = 0.75 nm and n = 3. Additionally, the phonon scattering mechanism was found to be the dominant contribution to the anomalous Hall effect (AHE) in our studied multilayers. These Co_2MnSi-based multilayers are promising candidates for spintronic devices due to their robust PMA and tunable interfacial effects, which are essential for high storage density and low-power operation.