One technology for high-density information storage employs magneto-optic thin films. Key material properties include a large magneto-optic Kerr rotation of polarized light (especially in the blue wavelength range), high perpendicular magnetic anisotropy, good reflectivity and a large magnetic coercivity. These can be achieved in nano-scale magnetic multilayers (e.g., Co-Pt) in which one of the constituent layers is ferromagnetic. Naturally the magnetic properties can be manipulated to a great extent by the preparation conditions, and the microstructure is most readily revealed by cross-section high-resolution electron microscopy (HREM). In our work, extremely high quality multilayers were fabricated by sputtering using a variety of inert gases, and most notably the influence of interface sharpness on properties was assessed. Intermetallic compounds, which are essentially “natural” multilayers, were also extensively studied.
Figure 1 shows magneto-optic Kerr rotation hysteresis loops for multilayers sputtered in 5 mtorr of either argon or the heavier xenon gas.