Fabrication and physical properties of the ferrimagnetic half-metallic Cr2MnAl films and nanowire arrays

Cr₂MnAl alloy was predicted to be a half-metallic ferrimagnet exhibiting metallic behavior in the spin-down channel and a semiconducting gap in the spin-up channel when crystallized in the Hg₂CuTi structure. However, this phase has not yet been experimentally synthesized. Here, we report the successful fabrication of Hg₂CuTi-structured Cr₂MnAl alloy in the form of thin films and nanowire arrays via magnetron sputtering. The degree of atomic ordering in Cr₂MnAl is close relative to the growth temperature. When the growth is set to room temperature, the optimal atomic ordering is achieved, resulting in a film with a saturation magnetization of 2 μ_B/f.u., consistent with the theoretical value of Hg₂CuTi-type atomic arrangement. The film exhibits a negative temperature coefficient of resistivity, attributed to highly localized carriers near the Fermi level as revealed through electronic structure analysis. Nanowire arrays were fabricated using porous anodized aluminum oxide (AAO) templates, and individual nanowires isolated after template dissolution and ultrasonic treatment. The easy-axis magnetization aligns with the nanowire growth direction, demonstrating significant perpendicular magnetic anisotropy.