Striations in YIG fibers grown by the laser-heated pedestal method

Yttrium iron garnet (YIG) single-crystal fibers of nominal composition Y3Fe 5O12 were grown by the laser-heated pedestal growth technique, a miniaturiz ed float-zone process. YIG fibers in diameters ranging from 100 to 740 mu m were grown at various rates and conditions, and analyzed by X-ray diffract ion, electron microprobe, IR-VIS spectroscopy, and light scattering tomogra phy. Infrared transparent YIG fibers were grown at rates below 10 mm/h in a ir. The transparency of the fibers was more dependent on the growth rate th an on the stability of the molten zone. Some striations and surface ridges containig a Fe-rich composition were observed at all growth rates. Light sc attering tomography studies revealed the presence of inclusions in some YIG fibers. Their size, density, composition and distribution depended on the growth conditions and molten zone stability. At growth rates below 10 mm/h, these defects and also the iron-oxide inclusions, which act as IR scatteri ng centers, were significantly reduced. (C) 2000 Elsevier Science B.V. All rights reserved.