Thickness dependence of coercivity in LPE garnet films

We have observed that thicker than normal LPE bubble garnet films (14–17 μm) have lower coercivity than those of normal thickness (3–5 μm). We have investigated this thickness dependence of 4 film compositions in the SmCaGe garnet system. In thin films, coercivity is dominated by a high coercivity region near the substrate. As the film thickness increases, the coercivity decreases approaching a ’’bulk’’ value. The two portions of the film, with their different properties, produce a linear relationship of coercivity versus reciprocal thickness which should be taken into account when comparing coercivities of LPE garnet films.