Effect of Ei3+ ions on structure, surface morphology, optical and magnetic properties of Tb-YIG nanocrystalline films

Nanocrystalline Y2.8-xTb0.2 Er-x Fe-5 O-12, (x = 0.0-2.6) films are successfully prepared under an annealed temperature of 900 degrees C in ambient oxygen using a sol-gel method. Structural investigations, using an Xray diffractometer, confirmed that all films have a crystallographic cubic phase of pure garnet. An increment of lattice constant was observed at lower concentrations (x <= 0.8), which then linearly decreased with higher concentrations; thus indicating a complete incorporation of Er+3 ions into the Tb: YIG structure. The surface morphology, obtained using field emission scanning electron microscopy and atomic force microscopy, showed a grain size nanostructure formation, a good adhesion of the film to the quartz substrate, and a smooth surface roughness. All samples showed high transparency in visible and near-infrared regions, with absorption edges below 500 nm. Vibrating sample magnetometer results at 29 degrees C revealed a formation of a soft ferrimagnetic material. Adding Er+3 ions reduced the saturation magnetization, M-s but, remarkably, increased the magnetic coercivity H-c. Based on a low absorption coefficient and saturation magnetization, the obtained films are a promising material for magneto optical devices, such as optical isolators in visible and near-infrared regions. (C) 2018 Elsevier B.V. All rights reserved.