Structural, magnetic, Mossbauer and magnetostrictive studies of amorphous Tb(Fe0.55Co0.45)(1.5) films

Films with a nominal composition of Tb(Fe0.55Co0.45)(1.5) were fabricated b y rf-magnetron sputtering from a fixed target configuration at various Ar g as pressures. Samples were investigated by means of x-ray diffraction (XRD) , scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), conversion electron Mossbauer spectra (CEMS) and magnetostriction measureme nts. As the Ar pressure increases, the Tb and Fe content increases slightly , whereas the Co content decreases. In addition, a small amount of Ar is in troduced into the films. The as-deposited films are amorphous alloys, but t heir magnetic behaviour depends strongly on the deposition conditions: a pe rpendicular magnetic anisotropy is obtained only in film deposited at lowes t Ar pressure and a parallel magnetic anisotropy exhibits in remaining film s. These samples show an intrinsic magnetostriction (lambda approximate to 10(-3)) in an applied field of 0.7 T. In this state, it was determined that the hyperfine field reaches the value B-hf = 24.5 T. Effects of the heat t reatment on the magnetostrictive softness are also reported. The parallel m agnetostriction with a huge magnetostrictive susceptibility (chi(lambda) = 1.8 X 10(-2) T-1) obtained at (mu(0)H = 10 mT) makes these materials useful for applications.