Annealing behaviour and crystal structure of RF-sputtered Bi-substituted dysprosium iron-garnet films having excess co-sputtered Bi-oxide content

Abstract

We investigate the magneto-optic properties, crystal structure and annealing behaviour of nano-composite media with record-high magneto-optic quality exceeding the levels reported so far in sputtered iron-garnet films. Bi-substituted dysprosium–gallium iron-garnet films having excess bismuth oxide content are deposited using RF co-sputtering, and a range of garnet materials are crystallized using conventional oven-annealing processes. We report, for the first time ever, the results of optimization of thermal processing regimes for various high-performance magneto-optic iron-garnet compositions synthesized and describe the evolution of the optical and magneto-optical properties of garnet-Bi-oxide composite-material films occurring during the annealing processes. The crystallization temperature boundaries of the system (BiDy) 3 (FeGa) 5 O 12 : Bi 2 O 3 are presented. We also report the results of x-ray diffraction and energy-dispersive x-ray spectroscopy studies of this recently developed class of high-performance magneto-optic composites. Our hypothesis of iron oxides being the cause of excess optical absorption in sputtered Bi-iron-garnet films is confirmed experimentally.