Growth parameters of Bi0.1Y2.9Fe5O12 thin films for high frequency applications

Abstract

• Growth parameters are reported for Bi 0.1 Y 2.9 Fe 5 O 12 thin films on Gd 3 Ga 5 O 12 . • Effect of Bi ions (at dodecahedral site) in Bi 0.1 Y 2.9 Fe 5 O 12 (111)–orientation shown. • Increase in ferromagnetic resonance linewidth in (111)–orientation is observed. • Thickness dependent magnetization dynamics is studied. • Four–fold anisotropy is seen in in–plane angular dependent study. The growth and characterization of Bismuth (Bi) substituted YIG (Bi–YIG, Bi 0.1 Y 2.9 Fe 5 O 12 ) thin films are reported. Pulsed laser deposited (PLD) films with thicknesses ranging from 20 to 150 nm were grown on Gadolinium Gallium Garnet substrates. Two substrate orientations of (100) and (111) were considered. The enhanced distribution of Bi 3+ ions at dodecahedral site along (111) is observed to lead to an increment in lattice constant from 12.379 Å in (100) to 12.415 Å in (111) oriented films. Atomic force microscopy images showed decreasing roughness with increasing film thickness. Compared to (100) grown films, (111) oriented films showed an increase in ferromagnetic resonance linewidth and consequent increase in Gilbert damping. The lowest Gilbert damping values are found to be (1.06±0.12) × 10 −4 for (100) and (2.30±0.36) × 10 −4 for (111) oriented films with thickness of ≈150 nm. The observed values of extrinsic linewidth, effective magnetization, and anisotropic field are related to thickness of the films and substrate orientation. In addition, the in–plane angular variation established four–fold symmetry for the (100) deposited films unlike the case of (111) deposited films. This study prescribes growth conditions for PLD grown single–crystalline Bi–YIG films towards desired high frequency and magneto–optical device applications.