Surface Morphology and Lattice Misfit in YIG and La:YIG Films Grown by LPE Method on GGG Substrate

摘要

Y_3Fe_5O_(12)(YIG) and La-doped YIG filmswere grown on the (111) GGG substrate using the PbO-B_2O_3flux system Pb, La incorporation and lattice misfit aridannealing behaviors were studied. In the case of LPE growth ofYIG film, lead ions from flux are substituted inevitably, andthey play an important role in controlling film misfit. For acomplete lattice matching, high supercooling is necessary inpure YIG growth, but this induces high defect concentration. Inthis experiment, La ions were added in the solution tosufficiently increase lattice parameter of the film grown underlow supercooling. The concentration of substituted Pb and Lawere increased as the growth temperature was lowered andgrowth rate increased. The effective distribution coefficient ofLa was about 0.2 at a supercooling of 30 deg C. The optimumgrowth conditions which bring about very small misfit weredetermined by measuring the misfit by double crystaldiffractometer. Strain distributions of pre-annealed and annealedsamples were investigated by triple crystal diffractometer.