Magnetic Properties of GdIG Films Grown by Chemical Vapor Deposition

GdIG films with thicknesses from 0.3 μ to 3.0 μ have been grown epitaxially on the (100), (110), (111), and (320) faces of yttrium aluminum garnet substrates by chemical vapor deposition in a reactor consisting of two concentric tubes. The influence of substrate temperature, transport rates of iron and gadolinium chloride, partial pressures of oxygen, water vapor, and HCl, and substrate position on film growth have been determined. It is shown that diffusion between the film and substrate causes a variation in the compensation temperature through the film volume. This results in an asymmetry in the coercive force about the compensation temperature and anomolous behavior in the Faraday-effect hysteresis loops. These observations are discussed in terms of several possible models.