PREPARATION AND MAGNETIC STUDIES OF MN50AL50 AL BILAYER FILMS/

Mn50Al50/Al bilayer films were fabricated on a glass substrate by rf m agnetron sputtering. The films were subsequently heat-treated in order to transform nonmagnetic MnAl E-phase to magnetic tau-phase. The addi tion of Al buffer layer could enhance the adhesion of the MnAl films, and for Mn50Al50/Al bilayer films with Al layer thickness between 5 an d 15 nm, we can obtain high saturation magnetization (>390 emu/cm(3)), and high coercivity (>2200 Oe) Mn50Al50/Al films for practical usage. Bending beam method analysis shows that the larger the residual stres s of the Mn50Al50/Al bilayer film is, the higher the coercivity is. Th e relations between the saturation magnetization, the coercivity and t he phase transition, the microstructures of the films are discussed. ( C) 1997 American Institute of Physics.