Investigation of Co Ions Diffusion in Gd₃Ga₅O₁₂ Single Crystals

Abstract

Spatial changes of properties of Gd3Ga5O12 (GGG) single crystals caused by diffusion of cobalt ions during high-temperature annealing (1200 • C, 24 h) in Co3O4 powder are investigated. The registration of these changes was carried out by optical spectrophotometry, microscopy and micro-Raman scattering methods. Changes in structure of near-surface layers of the crystal were investigated by X-ray diffraction technique. It was shown that the additional absorption induced by annealing is related to intra-center optical transitions in Co 2+ ions, which occupy tetrahedral positions in the garnet structure at the distances of 250-500 µm from the crystal surface. The dependence of induced absorption with depth has got a non-monotonous character with a maximum at 400 µm. A comparison of the results obtained by different methods allows to suppose that the thermal treatment of GGG in the presence of cobalt ions leads to formation of the structurally and chemically non-uniform layer with a width about 500 µm.

Investigation of the Interface of Y3Fe5O12/Gd3Ga5O12 Structure Obtained by the Liquid Phase Epitaxy

“…This assumption is consistent with the results of work [ 11 ] on the study of cobalt diffusion into GGG crystals, where, using micro‐Raman scattering and local spectrophotometry methods, it was found that Co ions are incorporated into crystals to a depth of 600 µm.…”

“…This method was successfully used previously in the works dedicated to studies of optical properties changes caused by diffusion in lithium niobate and GGG single crystals. [ 11,13 ]…”

“…At the same time, in papers in Refs. [11][12][13] authors propose to investigate the interdiffusion layers within lithium niobate and gadolinium gallium garnet in "parallel" geometry. In this case the probe of analytical instrument operates in the direction parallel to the surface (on the cross section of the epitaxial structure) through which the diffusion occurs and the probes scanning directory coincides with the direction of diffusion.…”

Comparative Investigations of Nanohardness and Impurity Distribution Profiles of Lithium Niobate Single Crystals Diffusion Doped by Copper Ions

“…Moreover, positive modification of properties (optical, electrophysical) of surface and subsurface layers in LN and other oxide crystals by means of diffusion or implantation of metal ions is another important practical problem …”

“…In refs. [], the optical properties of reduced LiNbO 3 and cobalt‐doped Gd 3 Ga 5 O 12 , respectively, were studied along the diffusion direction, with a scanning light beam propagating parallel to the modified surface. These experiments have provided new information about a thickness of diffusion‐modified layers in crystals and a spatial distribution of induced point defects and dopant ions in the layers.…”