Direct formation of ferromagnetic MnBi layers with perpendicular magnetic anisotropy by ion beam mixing

Abstract Multilayers of Mn/Bi deposited on glass, Al, and Si substrates were irradiated with 400 keV Xe + ions at temperatures ranging from 80 to 550 K. Irradiation from room temperature up to 500 K leads to the formation of ferromagnetic MnBi layers with the hexagonal c axis oriented perpendicular to the substrate surface. Strong perpendicular magnetic anisotropy was observed for the above specimens using X-ray diffraction and a vibrating sample magnetometer (VSM). Quenched metastable phases with ferromagnetism were not obtained for the Mn(25–50 at%)/Bi multilayers irradiated with 400 keV Xe + at temperatures of 80 to 550 K. A detailed discussion is made on the dependence of the magnetic properties of the ion-mixed layers on irradiation temperature, ion dose, and substrate species.