The effect of boron on the uniaxial magnetic anisotropy energy and the polar Kerr rotation in amorphous NdFe films

Amorphous light rare earth–transition metal alloys are candidates for magneto-optical recording materials in the wavelength region of a blue laser beam (λ≈400 nm) due to the large Kerr rotation angle θK. However, the large demagnetizing energy (shape anisotropy) prevents the films from developing an effective perpendicular anisotropy. The addition of boron to the amorphous Nd Fe matrix reduces the magnetization, enhances the effective perpendicular anisotropy, and enhances the Kerr rotation angle θK.