Magnetic properties of multilayers of nano thin Co,Ce-doped and undoped yttrium iron garnet films for magneto-optic applications

Improved magnetic properties of as-deposited multilayers consisting of alternate nano-thin films of Co,Ce-doped and undoped yttrium iron garnet (YIG) formed by low pressure chemical vapor deposition using metalo-organic precursors are described. Multilayer garnet films consistently show high Ms and Hc values, which depend on the period number and period thickness. Multilayer films also show increase in anisotropy in the direction perpendicular to film plane. Multilayers having doped and undoped YIG films in each period in the thickness ratio 25 nm/30 nm with 6 periods show high saturation magnetization, Ms value of 137 kA m−1 and high perpendicular to planer coercivity ratio ≈2. Maximum obtained coercivity, Hc for a 6 period, 14 nm/17 nm multilayer film was 197 kA m−1. Multilayer films do not a require high temperature 900 °C, 5 h oxygen annealing for realizing improved magnetic properties which is inevitably needed for single layer Co,Ce-YIG films. Thus, as-deposited multilayer garnet films offer considerable technological advantage for application in magneto-optic media.