Isotropic soft magnetic properties of CoFeAlCu films with (111) orientation

The dynamic behavior of the magnetization for (111)-oriented films with cubic crystalline structures has been studied theoretically, and the permeability for such textured films has been confirmed to be isotropic. Meanwhile, Co-rich CoFeAlCu films with high saturation magnetization (4 pi M(s) = 15.8 kG) and low magnetostriction (lambda(s) = 1.3 x 10(-6)), prepared by the dc sputtering method, are found to exhibit perfect fcc (111) orientation with grain size of about 400 Angstrom. A fairly good isotropic magnetic softness has been attained for CoFeAlCu films with Zr underlayers even in the as-sputtered state with H-c of about 1.5 Oe in every measuring direction. After annealing in a rotating magnetic field at 380 degrees C for 2 h, the magnetic softness is further improved with H-c as low as 0.85 Oe, and the permeability is isotropic in the film plane and as high as 500-600. The perfect (111) orientation of the CoFeAlCu films leads to the isotropic softness, which is consistent with the theoretical prediction. (C) 1996 American Institute of Physics.