Growth and characterization of high purity epitaxial yttrium iron garnet films grown from BaO–B2O3–BaF2 flux

The growth of yttrium iron garnet (YIG) epitaxial films of excellent purity from a lead-free BaO–B2O3–BaF2 flux and their characterization by the magnetic resonance methods are reported. The films were prepared by the standard dipping liquid-phase epitaxy onto gadolinium gallium garnet substrates of three crystallographic orientations (111), (110), and (100). The objective of utilization of a lead-free flux was to reduce the content of impurities and intrinsic defects in the garnet films and to obtain samples with minimum microwave losses. The samples exhibited very narrow NMR and spin wave linewidths. The diamagnetic and paramagnetic doping of YIG with ions of different valency and segregation of these ions between the garnet layer and the barium melt were also studied and the relevant distribution coefficients for doping into the tetrahedral (Ga, Al, Si Ge), octahedral (In) and dodecahedral (La, Ca) sites were determined.