5 7Fe-YIG: Narrow x-ray linewidth epitaxial layers on Gd3Ga5O12

Abstract

Epitaxial layers of 81% 57Fe-enriched Y3Fe5O12 were grown on thick, (100)-oriented substrates of Gd3Ga5O12 for experiments in resonant nuclear diffraction. Layers up to 10 μm thick were grown on each side of 32-mm-diam, 5-mm-thick wafers using techniques common for the growth of magnetic bubble materials, but with the use of a PbO-V2O5 flux in place of the usual PbO-B2O3 flux. The PbO-V2O5 flux offers a lower solubility of YIG which allows a reduction in the amount of 57Fe oxide required for layer growth. Thick substrates were used to reduce possible bowing from lattice constant mismatch. Lead incorporation onto yttrium lattice sites was controlled by adjusting the growth temperature, and this allowed a close lattice constant match between the layers and the substrate. Layer thickness was essentially uniform across the layer diameter with the edges 5% thicker than the center. Curie temperature and Faraday rotation measurements of the equivalent (111)-oriented material indicate as a formula unit (Y2.96Pb0.04)Fe3(Fe1.94Y0.06)O12. YIG/YIG double-crystal diffraction by tungsten L-γ1 irradiation of a 5×7-mm rectangular area of the first crystal gave a composite linewidth of 13 arcsec for the {400} reflection. This same linewidth was observed in synchrotron illumination of the central 80% of the area of the first layer. The possibility of linewidth reduction in this material is discussed.