Perpendicular Magnetic Anisotropy of TbCo Films

Abstract

An experimental study has been made on the magnetic anisotropy of amorphous TbCo films prepared by rf co-sputtering. TbCo films prepared at a substrate bias voltage of –100 V exhibit a large uniaxial anisotropy of 2×10 6 erg/cm 3 with its easy axis perpendicular to the film plane, whereas films prepared without the substrate bias exhibit the anisotropy with its easy axis in the film plane. The planar stress due to the substrate constraint considerably influences the perpendicular anisotropy through the large magnetostriction of about 2×10 -4 . When films with perpendicular anisotropy are removed from the substrate, the anisotropy energy decreases to 65–80 percent of its initial value. Annealing for one hour at 300°C destroys the perpendicular anisotropy almost completely.