Investigations into the Origin of Anisotropy in Oblique-Incidence Films

Experimental evidence is presented which shows that the magnetic anisotropy of oblique-incidence Permalloy and iron films is not caused by an inclined texture axis or anisotropic strain. Electron diffraction and microscopy have not yet revealed anisotropy in the crystalline microstructure of these films. These techniques have also thus far failed to reveal the existence of agglomeration of the crystallites into small groups having anisotropic geometric shapes. Magnetic anisotropy, on the other hand, was observed in Permalloy films deposited at normal incidence on non-magnetic metal films deposited at oblique incidence;this would suggest such an agglomeration mechanism. There is also some indication that oxygen may play a role in oblique-incidence magnetic anisotropy.